The holiness movement refers to a set of beliefs and practices emerging from 19th-century Methodism, and to a number of evangelical Christian denominations who emphasize those beliefs as a central doctrine in the late 19th century. The pioneering founder of the International [Apostolic] Holiness Church (IHC) is Martin Well Knapp(1853-1901). The movement or the Holiness Church is distinguished by its emphasis on the four-fold or Full gospel: Regeneration, Baptism with Holy Spirit as the entire sanctification and holiness experience, John Wesley's "Christian perfection" teaching—the belief that it is possible to live free of voluntary sin, and particularly by the belief that this may be accomplished instantaneously through a second work of grace. M. W. Knapp and his colleagues added "Divine Healing," "the Second Coming of Christ with "Overseas Missions" and "Female Ordination" to the double cure (salvation and Spirit-baptism) doctrines of the traditional holiness movement since 1897. Along with M. W. Knapp's missions, Korea, Japan, China(the Oriental Missionary Society [OMS] under the leadership of Martin and Minnie Knapp), India, Africa and S. America Holiness Church have developed a Full gospel or the four-fold gospel as the pure doctrines and evangelistic themes with the native ministries.
The key beliefs of the holiness movement or the International [Apostolic] Holiness Church (M. W. Knapp) are (1) regeneration by grace through faith, with the assurance of salvation by the witness of the Holy Spirit; (2) Spirit-baptism or entire sanctification as a second definite work of grace, received by faith, through grace, and accomplished by the baptism and power of the Holy Spirit, by which one is enabled to live a holy life; (3) Divine Healing; (4) the Pre-Millennial Second Coming of Christ, and (5) World Evangelization that had been originated by M. W. Knapp [the Constitution of the International Holiness Union/Church and Prayer League] since 1897.
In the context of the holiness movement, the first work of grace is salvation from sin. Adherents believe that without it, no amount of human effort can achieve holiness or Spirit-baptism [Pneumatology]. The movement's teaching on salvation is conventionally Protestant - God's people are saved by grace alone, through faith alone in Jesus Christ who made atonement for human sins.
Holiness adherents believe that the "second work of grace" refers to a personal experience subsequent to regeneration, in which the believer is cleansed of the tendency to commit sin. This experience of sanctification enables the believer to live a holy life, and ideally, to live entirely without wilful sin, though it is generally accepted that a sanctified individual is still capable of committing sin. M. W. Knapp had added divine healing and the second coming of Christ to the double cure doctrines with rescue and world mission since 1897.
Holiness groups believe the moral aspects of the law of God are pertinent for today, and so expect their adherents to obey behavioral rules - for example prohibiting the consumption of alcohol, participation in any form of gambling, and entertainments such as dancing and movie-going. This position does attract opposition from some evangelicals, who charge that such an attitude refutes or slights Reformation (particularly Calvinist) teachings that believers are justified by grace through faith and not through any efforts or states of mind on their part, that the effects of original sin remain even in the most faithful of souls.
Relation and reaction to Pentecostalism
The traditional holiness movement is distinct from the Pentecostal movement, which believes that the baptism in the Holy Spirit involves supernatural manifestations such as speaking in unknown tongues. Many of the early Pentecostals were from the holiness movement, and to this day many "classical Pentecostals" maintain much of holiness doctrine and many of its devotional practices. Additionally, the terms Pentecostal and apostolic, now used by adherents to Pentecostal and charismatic doctrine, were once widely used by holiness churches in connection with the consecrated lifestyle described in the New Testament. However, Pentecostals add and emphasize that the baptism of the Holy Spirit is evidenced specifically by supernatural manifestations, a position which churches in the traditional holiness movement do not accept.
During Azusa Street revival (often considered the advent of Pentecostalism), the practice of speaking in tongues was strongly rejected by leaders of the traditional holiness movement. Alma White, the leader of the Pillar of Fire Church, a holiness denomination, wrote a book against the Pentecostal movement that was published in 1936; the work, entitled Demons and Tongues, represented early rejection of the new Pentecostal movement. White called speaking in tongues "satanic gibberish" and Pentecostal services "the climax of demon worship".
However, most contemporary Holiness Churches believe in speaking in unknown tongues, some even agree with Pentecostalism in that speaking in unknown tongues is evidence of reception of the Holy Ghost 
The roots of the holiness movement are as follows:
- The Reformation itself, with its emphasis on salvation by grace through faith alone.
- Puritanism in 17th century England and its transplantation to America with its emphasis on adherence to the Bible and the right to dissent from the established church.
- Pietism in 17th century Germany, led by Philipp Jakob Spener and the Moravians, which emphasized the spiritual life of the individual, coupled with a responsibility to live an upright life.
- Quietism, as taught by the Religious Society of Friends (Quakers), with its emphasis on the individual’s ability to experience God and understand God’s will for himself.
- The 1730s Evangelical Revival in England, led by Methodists John Wesley and his brother Charles Wesley, which brought Wesley's distinct take on the Eastern Orthodox concept of Theosis and the teachings of German Pietism to England and eventually to the United States.
- The First Great Awakening in the 18th and early 19th centuries in the United States, propagated by George Whitefield, Jonathan Edwards, and others, with its emphasis on the initial conversion experience of Christians.
- The Second Great Awakening in the 19th century in the United States, propagated by Francis Asbury, Charles Finney, Lyman Beecher, Phoebe Palmer and others, which also emphasized the need for personal holiness and is characterized by the rise of evangelistic revival meetings.
- M. W. Knapp founded the Revivalist in 1883, the International [Pentecostal] Revival League and Prayer League and the Central Holiness League 1893, The International Holiness Union [Church] and Prayer League called the International Apostolic Holiness Church or the Pilgrim Holiness Church in the US. Knapp's Holiness Church in Cincinnati Ohio had the overseas branches in Korea, Japan, China, India, South Africa and South America and has constituted the largest Holiness group in the world with the IHC missions and its Oriental agent OMS.
The Methodists of the 19th century continued the interest in Christian holiness that had been started by their founder, John Wesley. They continued to publish Wesley's works and tracts, including his famous A Plain Account of Christian Perfection. From 1788 to 1808, the entire text of A Plain Account was placed in the Discipline of the Methodist Episcopal Church, and numerous persons in early American Methodism professed the experience of entire sanctification, including Bishop Francis Asbury.
By the 1840s, a new emphasis on holiness and Christian perfection had begun within American Methodism. Two major leaders of the holiness revival were Phoebe Palmer and her husband, Dr. Walter Palmer. In 1835, Palmer's sister, Sarah A. Lankford, had started holding Tuesday Meetings for the Promotion of Holiness in her New York City home. In 1837, Palmer experienced what she called entire sanctification and had become the leader of the Tuesday Meetings by 1839. At first only women attended these meetings, but eventually Methodist bishops and hundreds of clergy and laymen began to attend as well. At the same time, Methodist minister Timothy Merritt of Boston founded a journal called the Guide to Christian Perfection, later renamed The Guide to Holiness. This was the first American periodical dedicated exclusively to promoting the Wesleyan message of Christian holiness. In 1865, the Palmers purchased The Guide which at its peak had a circulation of 30,000. In 1859, Palmer published The Promise of the Father, in which she argued in favor of women in ministry. This book later influenced Catherine Booth, co-founder of the Salvation Army. The practice of ministry by women is common but not universal within the denominations of the holiness movement.
At the Tuesday Meetings, Methodists soon enjoyed fellowship with Christians of different denominations, including the Congregationalist Thomas Upham. Upham was the first man to attend the meetings, and his participation in them led him to study mystical experiences, looking to find precursors of holiness teaching in the writings of persons like German Pietist Johann Arndt and the Roman Catholic mystic Madame Guyon. Other non-Methodists also contributed to the holiness movement. During the same era Asa Mahan, the president of Oberlin College, and Charles Grandison Finney, an evangelist associated with the college, promoted the idea of Christian holiness. In 1836, Mahan experienced what he called a baptism with the Holy Spirit. Mahan believed that this experience had cleansed him from the desire and inclination to sin. Finney believed that this experience might provide a solution to a problem he observed during his evangelistic revivals. Some people claimed to experience conversion but then slipped back into their old ways of living. Finney believed that the filling with the Holy Spirit could help these converts to continue steadfast in their Christian life.
Representative was the revivalism of Rev. James Caughey, an American missionary sent by the Wesleyan Methodist Church to work in Ontario, Canada from the 1840s through 1864. He brought in the converts by the score, most notably in the revivals in Canada West 1851-53. His technique combined restrained emotionalism with a clear call for personal commitment, coupled with follow-up action to organize support from converts. It was a time when the Holiness Movement caught fire, with the revitalized interest of men and women in Christian perfection. Caughey successfully bridged the gap between the style of earlier camp meetings and the needs of more sophisticated Methodist congregations in the emerging cities.
Presbyterian William Boardman promoted the idea of holiness through his evangelistic campaigns and through his book The Higher Christian Life, which was published in 1858. Also, Hannah Whitall Smith, a Quaker, experienced a profound personal conversion. Sometime in the 1860s, she found what she called the "secret" of the Christian life—devoting one’s life wholly to God and God’s simultaneous transformation of one’s soul. Her husband, Robert Pearsall Smith, had a similar experience at the camp meeting in 1867. Methodist minister B. F. Haynes wrote a book, Tempest-Tossed on Methodist Seas, about his decision to leave the Methodist church and join the Church of the Nazarene. In it he described the bitter divisions within the Methodist church over the holiness movement.
The first distinct "holiness camp meeting" convened at Vineland, New Jersey in 1867 under the leadership of John S. Inskip, John A. Wood, Alfred Cookman, and other Methodist ministers. The gathering attracted as many as 10,000 people. At the close of the encampment, while the ministers were on their knees in prayer, they formed the National Camp Meeting Association for the Promotion of Holiness, and agreed to conduct a similar gathering the next year. This organization was commonly known as the National Holiness Association. Later, it became known as the Christian Holiness Association and subsequently the Christian Holiness Partnership.
The second National Camp Meeting was held at Manheim, Pennsylvania, and drew upwards of 25,000 persons from all over the nation. People called it a "Pentecost," and it did not disappoint them. The service on Monday evening has almost become legendary for its spiritual power and influence. The third National Camp Meeting met at Round Lake, New York. This time the national press attended and write-ups appeared in numerous papers, including a large two-page pictorial in Harper's Weekly. These meetings made instant religious celebrities out of many of the workers. Robert and Hannah Smith were among those who took the holiness message to England, and their ministries helped lay the foundation for the now-famous Keswick Convention.
In 1871, the American evangelist Dwight L. Moody had what he called an "endowment with power" as a result of some soul-searching and the prayers of two Free Methodist women who attended one of his meetings. He did not join the holiness movement but certainly advanced some of its ideas and even voiced his approval of it on at least one occasion.
In the 1870s, the holiness movement spread to Great Britain, where it was sometimes called the higher life movement after the title of William Boardman’s book The Higher Life. Higher life conferences were held at Broadlands and Oxford in 1874 and in Brighton and Keswick in 1875. The Keswick Convention soon became the British headquarters for the movement. The Faith Mission in Scotland was one consequence of the British holiness movement. Another was a flow of influence from Britain back to the United States. In 1874, Albert Benjamin Simpson read Boardman’s Higher Christian Life and felt the need for such a life himself. He went on to found the Christian and Missionary Alliance.
In the 1950s and 1960s, several small groups left the mainstream holiness movement to form what is known as the conservative holiness movement. During the 1968 merger of the Wesleyan Methodist Church and the Pilgrim Holiness Church which formed the Wesleyan Church, the Allegheny Conference and the Tennessee Conference of the Wesleyan Methodist Church(now known as the Bible Methodist Connection of Tennessee), and some churches of the Pilgrim Holiness Church did not approve of the merger and several new holiness denominations were formed.
There is an annual gathering in Huntington, West Virginia, called the Interchurch Holiness Convention. It has met for several years in Dayton, Ohio.
in English-speaking countries
The holiness movement led to the formation of several Christian organizations, including:
- United Methodist Church, some of them
- The Salvation Army
- The Church of the Nazarene
- The Wesleyan Church or the Pilgrim Holiness Church
- Free Methodist Church
- Freewill Baptist
- International Pentecostal Holiness Church
- Korea Evangelical Holiness Church with 8,000 churches, the largest
- Korea Jesus Holiness Sungkyul Church with 2,000 churches, separated from KEHC in 1961
- Korea Holiness Church of the Nazarne with 300 churches, separated from KEHC in 1948
- Korea Church of God with 200 churches, separated from KEHC in 1936
- Korea Evangelical Church of America with 300 churches of the KEHC US branch
- Southern Baptist Convention, some of them
- Russell, Thomas Arthur (June 2010). Comparative Christianity: A Student's Guide to a Religion and Its Diverse Traditions. Universal-Publishers. pp. 121–. ISBN 9781599428772. Retrieved 9 November 2012.
- The New International Dictionary of Pentecostal and Charismatic Movements, s.v. "Part II Global Statistics".
- Rybarczyk in Patterson and Rybarczyk 2007, p. 4.
- Vinson Synan, The Holiness-Pentecostal Tradition: Charismatic Movements in the Twentieth Century, (Grand Rapids, Michigan: William B. Eerdmans Publishing Company, 1997 2nd ed.), p. 8.
- Synan 1997, p. 17.
- Synan 1997, p. 18.
- Peter Bush, "The Reverend James Caughey and Wesleyan Methodist Revivalism in Canada West, 1851-1856," Ontario History, Sept 1987, Vol. 79 Issue 3, pp 231-250
- Pete, Reve M., The Impact of Holiness Preaching as Taught by John Wesley and the Outpouring of the Holy Ghost on Racism
- InterChurch Holiness Convention website
- Boardman, William E. The Higher Christian Life, (Boston: Henry Hoyt, 1858).
- Brown, Kenneth O. Holy Ground, Too, The Camp Meeting Famil Tree. Hazleton: Holiness Archives, 1997.
- Brown, Kenneth O. Inskip, McDonald, Fowler: "Wholly And Forever Thine." (Hazleton: Holiness Archives, 2000.)
- Cunningham, Floyd. T. " Holiness Abroad: Nazarene Missions in Asia. " Pietist and Wesleyan Studies, No. 16. Lanham, MD: Scarecrow Press, 2003.
- Cunningham, Floyd T. ed. "Our Watchword & Song: The Centennial History of the Church of the Nazarene." By Floyd T. Cunningham; Stan Ingersol; Harold E. Raser; and David P. Whitelaw. Kansas City, MO: Beacon Hill Press of Kansas City, 2009.
- Dieter, Melvin E. The Holiness Revival of the Nineteenth Century (Rowman & Littlefield, 1996).
- Grider, J. Kenneth. A Wesleyan-Holiness Theology, 1994 (ISBN 0-8341-1512-3).
- Hong, Paul Yongpyo, " Spreading the Holiness Fire: The History of OMS Korea Holiness Church 1902-1957." D. Miss dissertation of Fuller Theological Seminary (1996).
- Hong, Paul Yongpyo, " A History of the Korea Evangelical Holiness Church for 110 Years. " (Seoul: WWGT, 2010).
- Hong, Paul Yongpyo ed. " Pentecostal Holiness Theology With Regard To M. W. Knapp." (Seoul: Pentecost Press, 2013).
- Hong, Paul et al., " The Founders and Their Thoughts of the Holiness Movement in the Late 19th Century: M. W. Knapp, S. C. Rees, W. Godbey and A. M. Hills." (KEHC Love Press, 2014).
- Kostlevy, William C., ed. Historical Dictionary of the Holiness Movement (Rowman & Littlefield, 2001).
- Kostlevy, William C. Holy Jumpers: Evangelicals and Radicals in Progressive Era America (2010) on the influential Metropolitan Church Association in 1890s Chicago excerpt and text search
- Mannoia, Kevin W. and Don Thorsen. "The Holiness Manifesto", (William B. Eerdmans Publishing, 2008)
- Sanders, Cheryl J. Saints in exile: The Holiness-Pentecostal experience in African American religion and culture (Oxford University Press, 1999)
- Smith, Logan Pearsall, ed. Philadelphia Quaker: The Letters of Hannah Whitall Smith (New York: Harcourt, Brace and Co., 1950).
- Smith, Timothy L. Called Unto Holiness: The Story of the Nazarenes—The Formative Years, (Nazarene Publishing House, 1962).
- Spencer, Carol. Holiness: The Soul Of Quakerism" (Paternoster. Milton Keynes, 2007)
- Stephens, Randall J. The Fire Spreads: Holiness and Pentecostalism in the American South." (Cambridge, MA: Harvard University Press, 2008).
- Thornton, Wallace Jr. The Conservative Holiness Movement: A Historical Appraisal, 2014 excerpt and text search
- Thornton, Wallace Jr. When the Fire Fell: Martin Wells Knapp's Vision of Pentecostal and the Beginnings of God's Bible School " (Emeth Press, 2014).
- Thornton, Wallace Jr. From Glory to Glory: A Brief Summary of Holiness Beliefs and Practices 
- Thornton, Wallace Jr. Radical Righteousness: Personal Ethics and the Development of the Holiness Movement 
- White, Charles Edward. The Beauty of Holiness: Phoebe Palmer as Theologian, Revivalist, Feminist, and Humanitarian (Zondervan/Francis Asbury Press, 1986).
- McDonald, William and John E. Searles. The Life of Rev. John S. Inskip, President of the National Association for the Promotion of Holiness (Chicago: The Christian Witness Co., 1885).
- Smith, Hannah Whitall. The Unselfishness of God, and How I Discovered It: A Spiritual Autobiography (New York: Fleming H. Resell Co., 1903).
- Holiness history from the Global Anabaptist Mennonite Encyclopedia Online
- "The Cleansing Wave", article from Christianity Today
- "Holiness Movement: Dead or Alive," article by Keith Drury (CRI Voice)
- A Look At Holiness And Perfectionism Theology by Armin J. Panning
- Christian Cyclopedia article on Holiness Churches
- How They Entered Canaan: A collection of holiness experience accounts by B. G. Paddock