Efficacy of prayer
The efficacy of prayer has been the topic of various studies since Francis Galton first addressed it in 1872. According to the Washington Post, "...prayer is the most common complement to mainstream medicine, far outpacing acupuncture, herbs, vitamins and other alternative remedies." The largest and most scientifically rigorous study of prayer's efficacy, the 2006 STEP project, found no significant difference whether subjects were prayed for or not, except some negative effects among those who knew they were receiving prayers. Dr. Fred Rosner, an authority on Jewish medical ethics, has expressed doubt that prayer could ever be subject to empirical analysis.
On the issue of intercessory prayer, Christian teachings have emphasized the need for guidance from the Holy Spirit as to what needs to be prayed for and have taught that "God can not be coerced."
The philosophical controversy on this topic even involves the basic issues of statistical inference and falsifiability as to what it may mean to "prove" or "disprove" something, and the problem of demarcation, i.e., as to whether this topic is even within the realm of science at all.
In comparison to other fields that have been scientifically studied, carefully monitored studies of prayer are relatively few. The field remains tiny, with about $5 million spent worldwide on such research each year.
- 1 Studies on the efficacy of prayer
- 2 Classes of studies
- 3 Belief and skepticism
- 4 Religious and philosophical issues
- 5 See also
- 6 References
- 7 External links
Studies on the efficacy of prayer
A number of studies have been performed to scientifically measure the impact of prayer, often within a medical setting. The studies performed have used different structural methods and measured both hard data (such as blood pressure variations) and soft data such as anxiety levels and number of doctor visits. They have measured first-person effects (where the beneficiary performs the prayer), second-person effects (where someone with a personal connection to the beneficiary performs the prayer), and third-party effects where a group of unknown people pray for the beneficiary.
What can be measured?
Almost all second- and third-party studies have focused on intercessory prayers or direct petitions to God, while first-person studies have measured meditative prayers as well. In general, the requested outcome for a prayer as petition may be either an event in the physical world, e.g. the recovery of a person from an ailment, or an event in the spiritual world, e.g., the repose of a soul via a prayer for the dead. There are, of course, also certain types of prayer whose efficacy can not (by definition) be measured in the physical world, e.g. Roman Catholic tradition includes specific prayers and devotions as acts of reparation which do not involve a petition for a living or deceased beneficiary, but aim to repair the sins of others, e.g., for the repair of the sin of blasphemy.
In most cases, the parameters measured within the medical studies cited here have not been all-encompassing from scientific or religious viewpoints. Mental attributes such as reverence, which are emphasized by religious figures such as popes and saints, have not been measured. The studies have also not measured whether meditation prior to prayer affects the outcome.
The studies cited here have also generally not measured physical parameters, such as "proximity to the nearest place of common worship", e.g., does a prayer by a Christian within a church have more effect than outside a church? Does it vary by the size of church? Does the effect increase or decrease if the Christian prays inside a Buddhist temple? What about a Buddhist praying in a church? Do prayers during Christmas have more or less effect than at other times of the year? And the distance between the beneficiary and the location of the prayer has not been clarified in the studies, e.g., does prayer for a person who is a continent away have the same effect as prayers for a person who is inches away? Does the "skill level" of the person praying have an effect on the outcome as stipulated by Wisneski and Anderson in their book The Scientific Basis of Integrative Medicine?
Wisneski and Anderson also hypothesize that different individuals have varying "prayer aptitude levels," just as different people have varying levels of athletic ability, and that the effect of prayer is the combined effects of ability and training. Pope John Paul II echoed that sentiment when he said: "We have to learn to pray: as it were learning this art ever anew..." And he opposed "mechanical prayer" and emphasized the need for self-reflection before prayer. The familiarity of the person praying with the words and method of praying, and their distraction level before they start to pray is not measured as a parameter in some[which?] studies.
The reverence with which the prayer is recited has been emphasized by other religious writers, such as St. Louis de Montfort in his book Secret of the Rosary. In section 41, he emphasized the "purity of intention" and stated that it is not the length of a prayer that matters, but the fervor, purity, and respect with which it is said, e.g., a single properly said Hail Mary is worth many that are badly said. Sections 42 and 43 of Montfort's book are devoted to "Attention" and "Fighting Distractions".
Classes of studies
First person studies
An example of a study on meditative prayer was the Bernardi study in the British Medical Journal in 2001. It reported that by praying the rosary or reciting yoga mantras at specific rates, baroreflex sensitivity increased significantly in cardiovascular patients.
A study published in 2008 used Eysenck's dimensional model of personality based on neuroticism and psychoticism to assess the mental health of high school students based on their self-reported frequency of prayer. For students both in Catholic and Protestant schools, higher levels of prayer were associated with better mental health as measured by lower psychoticism scores. However, among pupils attending Catholic schools, higher levels of prayer were also associated with higher neuroticism scores.
Many accept that prayer can aid in recovery due to psychological and physical benefits. It has also been suggested that if a person knows that he or she is being prayed for it can be uplifting and increase morale, thus aiding recovery. (See Subject-expectancy effect.) Many studies have suggested that prayer can reduce physical stress, regardless of the god or gods a person prays to, and this may be true for many reasons. According to a study by Centra State Hospital, "the psychological benefits of prayer may help reduce stress and anxiety, promote a more positive outlook, and strengthen the will to live." Other practices such as Yoga, T'ai chi, and Meditation may also have a positive impact on physical and psychological health.
A 2001 study by Meisenhelder and Chandler analyzed data obtained from 1,421 Presbyterian pastors surveyed by mail and found that their self-reported frequency of prayer was well-correlated with their self-perception of health and vitality. This research methodology has inherent problems with self-selection, selection bias, and residual confounding, and the authors admitted that the direction of perceived prayer and health relationships "remains inconclusive due to the limits of the correlational research design".
Second person studies
One condition that may affect the efficacy of intercessory prayer is whether the person praying has a connection to the person prayed for. A 2005 study published by The Journal of Alternative and Complementary Medicine alleges evidence that eleven healers in a variety of "distant intentionality" (defined as "sending thoughts at a distance") modalities were able to remotely influence the MRI-measurable brain activity in chosen partners who were physically and electrically isolated. As the authors explained, "the study is not about healing per se, but whether there is some correlation in the intention to connect at a distance with a person." The experiment has not yet been reproduced by the authors or by others.
Third party studies
The Victorian scientist Francis Galton made the first statistical analysis of third-party prayer. He hypothesized, partly as satire, that if prayer was effective, members of the British Royal Family would live longer than average, given that thousands prayed for their well-being every Sunday, and he prayed over randomized plots of land to see if the plants would grow any faster, and found no correlation in either case.
The amount of formal research performed on intercessory prayer is quite small, with about $5 million spent worldwide on such research each year. The parameters used within the study designs have varied, for instance, daily or weekly prayers, whether to provide patient photographs, with full or partial names, measuring levels of belief in prayer, and whether patients underwent surgery.
The third party studies have all been performed using Christian prayers, and reported either null results, correlated results, or contradictory results in which beneficiaries of prayer had worsened health outcomes. For instance, a meta-analysis of several studies related to distant intercessory healing published in the Annals of Internal Medicine in 2000 looked at 2774 patients in 23 studies, and found that 13 showed statistically significant positive results, 9 showed no effect, and 1 showed a negative result.
A 2003 levels of evidence review found evidence for the hypothesis that "Being prayed for improves physical recovery from acute illness". It concluded that although "a number of studies" have tested this hypothesis, "only three have sufficient rigor for review here" (Byrd 1988, Harris et al. 1999, and Sicher et al. 1998). In all three, "the strongest findings were for the variables that were evaluated most subjectively, raising concerns about the possible inadvertent unmasking of the outcomes assessors. Other meta-studies of the broader literature have been performed showing evidence only for no effect or a potentially small effect. For instance, a 2006 meta analysis on 14 studies concluded that there is "no discernable effect" while a 2007 systemic review of intercessory prayer reported inconclusive results, noting that 7 of 17 studies had "small, but significant, effect sizes" but the review noted that the three most methodologically rigorous studies failed to produce significant findings.
Secondary, inter-personal effects
Apart from whether prayer affects other beneficiaries, research has suggested that prayer has benefits on the person performing the prayer, e.g. in May 2011 a study was conducted that suggested a "significant specific indirect effect" between meditative prayer and hope, adult attachment, and forgiveness. Research has also suggested that prayer has a direct relation to a sense of overall gratitude in life. Prayer may also aid those dealing with alcoholism, e.g. a 2010 study suggested that there is a strong correlation between prayer and reduction of alcohol consumption. Those who actively pray during the week reported half as many consumed alcoholic drinks.
An increasingly more researched area within psychology of religion has been the relational implications of prayer, e.g. a study in 2011 conducted by Lambert et al. stated that when compared to a control group that experienced positive interactions with their significant other those in the prayer condition reported much higher feelings of unity and trust toward their significant other. Studies have also shown that there are increased feelings of marital enrichment through prayer. A study conducted in 2010 has also shown a correlation between prayer within relationships and reduction of infidelity. As with other areas of research about prayer, some debate whether these effects are a result of the prayer or a "placebo effect." However, Dr. Herbert Benson, a professor of medicine at Harvard Medical School, suggests that they may not be mutually exclusive.
Belief and skepticism
An article in the Medical Journal of Australia says that "One common criticism of prayer research is that prayer has become a popular therapeutic method for which there is no known plausible mechanism."
Medical professionals are skeptical of new claims by studies until they have been experimentally reproduced and corroborated. For instance, a 2001 study by researchers associated with Columbia University has been associated with controversy, following claims of success in the popular media. 
In the early 20th century, Florence Nightingale, a pioneer of modern nursing, was a believer in the effects of prayer. She wrote, "Often when people seem unconscious, a word of prayer reaches them".
Today, Although different medical studies have been at odds with one another, physicians have not stopped studying or recommending prayer. This may be partly because prayer is increasingly used as a coping mechanism for patients. According to Larry Dossey M.D.: "In 1993, only three U.S. medical schools had courses devoted to exploring the role of religious practice and prayer in health; currently, nearly 80 medical schools have instituted such courses", though many factors other than the efficacy of prayer are involved in such courses.
Different approaches to medicine
Skepticism on scope of prayer
|This article or section possibly contains previously unpublished synthesis of published material that conveys ideas not attributable to the original sources. (March 2012)|
In a debate/interview in Newsweek with Christian evangelical Rick Warren, atheist Sam Harris commented that most lay perceptions of the efficacy of prayer (personal impressions as opposed to empirical studies) were related to sampling error because "we know that humans have a terrible sense of probability." That is, humans are more inclined to recognize confirmations of their faith than they are to recognize disconfirmations.
Harris also criticized existing empirical studies for limiting themselves to prayers for relatively unmiraculous events, such as recovery from heart surgery. He suggested a simple experiment to settle the issue:
Get a billion Christians to pray for a single amputee. Get them to pray that God regrow that missing limb. This happens to salamanders every day, presumably without prayer; this is within the capacity of God. I find it interesting that people of faith only tend to pray for conditions that are self-limiting.
Within Christian teachings, the comment by Harris regarding what he called the self-limiting nature of prayer had been addressed years before by multiple authors. For instance, in the 19th century William Peabody discussed the efficacy of prayer in the face of what he called the immutability of the laws of nature. He said:
Night follows day, and day night. The seasons preserve their succession... We may not hope to suspend their operation by our prayers... And yet notwithstanding all of this, we hold in an undoubting faith the doctrine of the efficacy of our prayers, or to use the language of another, "of an influence from above as diversified and unceasing as are the requests from below".
Peabody then argued at length that prayers may have efficacy in a form that does not interfere with the arrangement of the laws of nature, and that God may respond in ways that are not anticipated, without changing the arrangement of nature. George Burnap echoed the same concept when he wrote:
God governs the universe by fixed and uniform laws, not only for the sake of order, but for human good... The fulfillment of every human desire would break up this order, and bring everything into disorder and confusion.
Prayers and miracles
The view expressed by Harris above regarding the "relatively unmiraculous" petitions used in prayers has been addressed in religious circles in the context of miraculous outcomes for prayer. There are different theological classifications of miracles, one of the most common being the three categories: "surpassing nature" (Latin supra naturam), "against nature" (Latin contra naturam) and "alongside nature" (Latin praeter naturam).
The raising of the dead is considered a "supra naturam" event and is not reported in theological writings beyond the Christian Bible, where ten resurrection events are recorded. Contra naturam events require significant changes to the "order of the world" (e.g. regrowth of limbs) and are also hardly ever reported. Praeter naturam events can proceed along the laws of nature. They have been reported in a number of cases, and have been subject to a large amount of debate. Examples include the claims of miraculous cures at pilgrimage site such as Our Lady of Lourdes. Many of these claims have been analyzed and only a few have been accepted by the Lourdes Medical Bureau.
The scientific measurement of the efficacy of massive prayer requires the coordination of the activities of a large number of people, and no direct citations for the existence of such studies appear in the scientific literature. However, non-scientific instructions for massive prayer have been issued in the past, and conclusions about the effects of the prayer have been drawn by a large number of believers, outside a scientific framework.
In a historical context, in 1571 Pope Pius V called for all of Europe to pray the Rosary for victory at the Battle of Lepanto, in which the Christian belligerents included the Papal States. Trophies from the battle are now enshrined in various Christian churches which attribute the victory to the massive prayers.
Directions for even more massive, long term prayers were provided by the messages of Our Lady of Fatima reported by Lucia Santos, who stated that the Virgin Mary specifically asked believers to pray for the conversion of Russia. The 9-day Fatima Novena prayer includes a petition for the conversion of Russia. With a blessing from Pope Pius XII (who called himself "the world chief against communism") millions of members of the Blue Army of Our Lady of Fatima were instructed to pray for several years in publications such as Soul Magazine. Some[who?] Christians attribute the fall of communism in the Revolutions of 1989 to massive prayers, while economists attribute them to market forces and socioeconomic conditions. 
Religious and philosophical issues
Religious and philosophical objections to the very study of prayer's efficacy exist. Many interpret Deuteronomy (6:16 "You shall not put the Lord your God to the test") to mean that prayer cannot, or should not, be examined.
The religious viewpoint objects to the claim that prayer is susceptible to experimental designs or statistical analysis, and other assumptions in many experiments, e.g. that a thousand prayers are statistically different from one. The objections also include the complaint that religion generally deals with unique, uncontrollable events; statistics, and science in general, deal with recurring phenomena which are possible to sample or control and are susceptible to general laws.
Religious objections also include the complaint that as prayer starts to be measured, it is no longer real prayer once it gets involved in an experiment and that the concept of conducting prayer experiments reflects a misunderstanding of the purpose of prayer. The 2006 STEP experiment indicated that some of the intercessors who took part in it complained about the scripted nature of the prayers that were imposed to them, saying that this is not the way they usually conduct prayer:
Prior to the start of this study, intercessors reported that they usually receive information about the patient's age, gender and progress reports on their medical condition; converse with family members or the patient (not by fax from a third party); use individualized prayers of their own choosing; and pray for a variable time period based on patient or family request.
To pray for particular favors is to dictate to Divine Wisdom, and savors of presumption; and to intercede for other individuals or for nations, is to presume that their happiness depends upon our choice, and that the prosperity of communities hangs upon our interest.
During the 20th-century, philosopher Bertrand Russell believed that religion and science "have long been at war, claiming for themselves the same territory, ideas and allegiances". And Russell believed that the war had been decisively won by science. Almost 40 years earlier, a 22-year-old Russell also wrote: "For although I had long ceased to believe in the efficacy of prayer, I was so lonely and so in need of some supporter such as the Christian God, that I took to saying prayers again when I ceased to believe in their efficacy."
The 21st-century evolutionary biologist Richard Dawkins, describing how Richard Swinburne explained away the STEP experiment's negative results "on the grounds that God answers prayers only if they are offered up for good reasons", says that some[which?] elements of religion are testable.
Other theologians joined NOMA-inspired sceptics in contending that studying prayer in this way is a waste of money because supernatural influences are by definition beyond the reach of science. But as the Templeton Foundation correctly recognized when it financed the study, the alleged power of intercessory prayer is at least in principle within the reach of science. A double-blind experiment can be done and was done. It could have yielded a positive result. And if it had, can you imagine that a single religious apologist would have dismissed it on the grounds that scientific research has no bearing on religious matters? Of course not.
The Holy Spirit and Christian teaching
John Tillotson, the 17th-century Archbishop of Canterbury argued that the efficacy of prayer depends on the Holy Spirit. Reformed Presbyterian scholar Wayne R. Spear argues that the person praying needs to be "guided by the Holy Spirit" as to what needs to be prayed for and that given the "right petition" the Holy Spirit will then intercede for the prayer.
The Catechism of the Catholic Church states that:
- "Christian prayer is a covenant relationship between God and man in Christ. It is the action of God and of man, springing forth from both the Holy Spirit and ourselves, wholly directed to the Father, in union with the human will of the Son of God made man."  "The Holy Spirit who teaches the Church and recalls to her all that Jesus said also instructs her in the life of prayer, inspiring new expressions of the prayer: blessing, petition, intercession, thanksgiving and praise." "Christian prayer is a communion of love with the Father, not only through Christ but also in him". "The father gives us when our prayer is united with that of Jesus 'another Counselor, to be with [us] for ever', the Spirit of Truth."  "The [Holy] Spirit helps us in our weakness; for we do not know how to pray as we ought, but the Spirit himself intercedes with sighs too deep for words." 
- "One enters into prayer by the narrow gate of faith. It is the face of the Lord that we seek and desire; it is his Word that we want to hear and keep" "Once committed to conversion, the heart learns to pray in faith. Faith is a filial adherence to God beyond what we feel and understand. It is possible because the Son gives us access to the Father. He can ask us to 'seek' and to 'knock', since he himself is the door and the way.
Christian existentialist philosopher and theologian Paul Tillich argued that prayer is not possible in a subject-object dichotomy in which the person is separated from God, for God cannot be the object of a prayer without being at the same time the subject.
- Researchers Look at Prayer and Healing, Washington Post, March 24, 2006
- BENEDICT CAREY, Long-Awaited Medical Study Questions the Power of Prayer New York Times, March 31, 2006 (accessed Nov. 17 2013)
- Realized religion: research on the relationship between religion and health Theodore J. Chamberlain, Christopher Alan Hall 2007 ISBN 1-890151-53-X pages 33-35
- Intercessory Prayer: Modern Theology, Biblical Teaching And Philosophical Thought by Philip Clements-Jewery 2005 ISBN 0-7546-3828-6 page 24-27
- The works of Dr. John Tillotson, Volume 10 by John Tillotson, Thomas Birch 2009 ISBN 0-217-76300-6 pages 99-105
- Talking to God: the theology of prayer by Wayne R. Spear 2002 ISBN 1-884527-13-2 pages 58-61
- Washington Post
- Catholic Encyclopedia http://www.newadvent.org/cathen/12775a.htm
- Leonard Wisneski, 2004, The Scientific Basis of Integrative Medicine, Taylor & Francis Publishing, ISBN 978-0-8493-2081-1 pp 248.
- Vatican Message of Pope John Paul II on Prayer
- Pope John Paul II "The Way to Christ" ISBN 978-0060642167[page needed]
- Saint Louis de Montfort, The Secret of the Rosary, Tan Books & Publisher, 1976. ISBN 978-0-89555-056-9 .[page needed]
- Bernardi L, Sleight P, Bandinelli G; et al. (2001). "Effect of rosary prayer and yoga mantras on autonomic cardiovascular rhythms: comparative study". BMJ 323 (7327): 1446–9. doi:10.1136/bmj.323.7327.1446. PMC 61046. PMID 11751348.
- Francis, Leslie; Robbins, Mandy; Lewis, Christopher Alan; Barnes, L. Philip (2008). "Prayer and psychological health: A study among sixth-form pupils attending Catholic and Protestant schools in Northern Ireland". Mental Health, Religion & Culture 11 (1): 85–92. doi:10.1080/13674670701709055.
- Mind and Spirit from the Health Library section of CentraState Healthcare System. Accessed May 18, 2006. Archived October 12, 2007 at the Wayback Machine
- Meisenhelder, Janice Bell; Chandler, Emily N. (2001). "Frequency of Prayer and Functional Health in Presbyterian Pastors". Journal for the Scientific Study of Religion 40 (2): 323–330. doi:10.1111/0021-8294.00059.
- Bhutkar, Pratima M.; Bhutkar, Milind V.; Taware, Govind B.; Doijad, Vinayak; Doddamani, B. R. (2008). "Effect of Suryanamaskar Practice on Cardio-respiratory Fitness Parameters: A Pilot Study" (PDF). Al Ameen Journal of Medical Sciences 1 (2): 126–9.
- Achterberg J, Cooke K, Richards T, Standish LJ, Kozak L, Lake J (December 2005). "Evidence for correlations between distant intentionality and brain function in recipients: a functional magnetic resonance imaging analysis". Journal of Alternative and Complementary Medicine 11 (6): 965–71. doi:10.1089/acm.2005.11.965. PMID 16398587.
- Galton, Francis. "Statistical Inquiries into the Efficacy of Prayer". Retrieved 7 May 2015.
- Galton, Francis (1872). "Statistical Inquiries into the Efficacy of Prayer". Fortnightly Review (68): 125–35. As found in The Prayer-Gauge Debate. Boston: Congregational Publishing Society. 1876. LCCN 39018081. OCLC 1809220.
- Richard Dawkins, 2006, "The God Delusion", Bantam Press: ISBN 0-618-68000-4, p. 61.
- Boorstein, Michelle. Researchers Stepping Up Study of Health And Religiosity, Washington Post, 6 December 2008.
- John A. Astin, et al. The Efficacy of "Distant Healing" A Systematic Review of Randomized Trials Annals of Internal Medicine June 6, 2000 vol. 132 no. 11 903-910 
- Powell LH, Shahabi L, Thoresen CE (January 2003). "Religion and spirituality. Linkages to physical health". The American Psychologist 58 (1): 36–52. doi:10.1037/0003-066X.58.1.36. PMID 12674817.
- David R. Hodge, "A Systematic Review of the Empirical Literature on Intercessory Prayer" in Research on Social Work Practice March 2007 vol. 17 no. 2 174-187 doi:10.1177/1049731506296170 Article abstract Full length article
- K. Masters, G. Spielmans, J. Goodson "Are there demonstrable effects of distant intercessory prayer? A meta-analytic review." Annals of Behavioral Medicine 2006 Aug;32(1):21-6. 
- Jankowski, Peter; Sandage, Steven (May 2011). "Meditative Prayer, Hope, Adult Attachment, and Forgiveness: A Proposed Model". Psychology of Religion and Spirituality 3 (2): 115–131. doi:10.1037/a0021601.
- Lambert, Nathaniel; Fincham, Frank; Braithwaite, Scott; Graham, Steven; Beach, Steven (August 2009). "Can Prayer Increase Gratitude". Psychology of Religion and Spirituality 1 (3): 139–149. doi:10.1037/a0016731.
- Lambert, Nathaniel; Fincham, Frank; Marks, Loren; Stillman, Tyler (June 2010). "Invocations and Intoxication: Does Prayer Decrease Alcohol Consumption". Psychology of Addictive Behaviors 24 (2): 209–219. doi:10.1037/a0018746.
- Lambert, Nathaniel; Fincham, Frank; LaVallee, Dana; Brantley, Cicely (6 June 2011). "Praying Together and Staying Together: Couple Prayer and Trust". Psychology of Religion and Spirituality.
- Beach, Steven; Hurt, Tera; Fincham, Frank; Franklin, Kameron; McNair, LIly; Stanley, Scott (August 2011). "Enhancing Marital Enrichment Through Spirituality: Efficacy Data for Prayer Focused Relationship Enhancement". Psychology of Religion and Spirituality 3 (3): 201–216. doi:10.1037/a0022207.
- Finchanm, Frank; Lambert, Nathaniel; Beach, Steven (October 2011). "Faith and Unfaithfulness: Can Praying for Your Partner Reduce Infidelity?". Journal of Personality and Social Psychology 99 (4): 649–659. doi:10.1037/a0019628.
- on YouTube
- "eMJA: Prayer as medicine: how much have we learned?". Retrieved 2007-12-21.
- Skeptical Inquirer, Sept/Oct 2004
- Reproductive Medicine Nov 2004
- The collected works of Florence Nightingale http://www.sociology.uoguelph.ca/fnightingale
- Wacholtz, Amy; Sambamoorthi, Usha (May 2011). "National Trends in Prayer Use as a Coping Mechanism for Health Concerns: Changes from 2002 to 2007". Psychology of Religion and Spirituality 3 (2): 67–77. doi:10.1037/a0021598.
- "Dr. Larry Dossey's Official Website". Retrieved 2007-12-21.
- VandeCreek, Larry; Dossey, Larry (1998). Scientific and pastoral perspectives on intercessory prayer: an exchange between Larry Dossey, M. D. and health care chaplains. New York: Haworth Pastoral Press. ISBN 1-56023-113-0.[page needed]
- Understanding Medical Physiology by R.L. Bijlani 2004 ISBN 81-8061-221-X page 916
- Alternative Medicine by Dónal O'Mathúna 2006 ISBN 978-0-310-26999-1 pages 236-239
- Mosby's complementary and alternative medicine by Lynda W. Freeman 2004 ISBN 0-323-02626-5 page 544
- Health, the individual, and integrated medicine by David Aldridge 2004 ISBN 978-1-84310-232-8 pages 120-122
- 'The God Debate' by Sam Harris, Rick Warren, Newsweek - RichardDawkins.net
- William Bourn Oliver Peabody, Efficacy of prayer, in "Sermons" B.H. Greene Press, Boston, 1849, pages 252-255
- George Burnap, The efficacy of prayer in "Christianity, its essence and evidence" Crosby, Nichols and Co. Boston, 1855 page 171
- Francois Leuret, 2006 Modern Miraculous Cures - A Documented Account Of Miracles And Medicine In The 20th Century ISBN 1-4067-9918-1 pages 34-35
- EWTN on Battle of Lepanto (1571) 
- Gilbert Chesterton, 2004, Lepanto, Ignatius Press ISBN 1586170309[page needed]
- Lucia Santos, 1995, Fatima In Lucia's Own words, The Ravengate Press, ISBN 0-911218-10-6 p104
- Fatima Novena
- Fatima Novena
- Blue Army History
- John Haffert, 1982, Dear Bishop, the History of the Blue Army, AMI Press ISBN 0911988424[page needed]
- Thomas Petrisko, 1998, Fatima Prophecies, St. Andrews Press, ISBN 978-1-891903-30-4 p 167
- Weekly Standard on Fatima
- Time Magazine on Fatima 
- Robert Daniels, 2007, The Rise and Fall of Communism in Russia, Yale University Press, ISBN 0300106491[page needed]
- Jacques Lévesque, 1997, The Enigma of 1989: The USSR and the Liberation of Eastern Europe University of California Press ISBN 978-0520206311[page needed]
- Deuteronomy 6:16
- Benson H, Dusek JA, Sherwood JB; et al. (April 2006). "Study of the Therapeutic Effects of Intercessory Prayer (STEP) in cardiac bypass patients: a multicenter randomized trial of uncertainty and certainty of receiving intercessory prayer". American Heart Journal 151 (4): 934–42. doi:10.1016/j.ahj.2005.05.028. PMID 16569567. Lay summary (PDF) – John Templeton Foundation (April 5, 2006).
- William Paley, 1835, Paley's moral and political philosophy Uriah Hunt Press, Philadelphia page 157
- Bertrand Russell, Religion and science Oxford University Press, 1997 ISBN 0-19-511551-1 page xi
- Bertrand Russell, The Collected Papers of Bertrand Russell: Cambridge Essays Published by Routledge, 1983 ISBN 0-04-920067-4
- Richard Swinburne, Response to a Statistical Study of the Effect of Petitionary Prayer, originally in Science and Theology News 2006.
- Dawkins, "The God Delusion", p. 65
- Catechism of the Catholic Church, 2564
- Catechism of the Catholic Church, 2644
- Catechism of the Catholic Church, 2615
- Catechism of the Catholic Church, 741
- from Catechism of the Catholic Church, 2656
- Catechism of the Catholic Church, 2609
- Paul Tillich, Courage to Be. p. 185.
|Wikiquote has quotations related to: Efficacy of prayer|
|Wikimedia Commons has media related to Prayer.|