|Beliefs and practices|
Succession to Muhammad
Imamate of the Family
Mourning of Muharram
Intercession · Ismah
The Occultation · Clergy
|The Qur'an · Sahaba
|Ashura · Arba'een · Mawlid
Eid ul-Fitr · Eid al-Adha
· Ismāʿīlī · Zaidi
The verse of purification
Mubahala · Two things
Khumm · Fatimah's house
First Fitna · Second Fitna
The Battle of Karbala
|Muhammad · Ali · Fatimah
Hasan · Hussein
|List of Shia companions|
|Fatimah · Khadijah · Zaynab bint Ali · Fatimah bint al-Hasan · Sukayna bint Husayn · Rubab · Shahrbanu · Nijmah · Fātimah bint Mūsā · Hakimah Khātūn · Narjis · Fatimah bint Asad · Farwah bint al-Qasim ·|
‘Iṣmah or ‘Isma (Arabic: عِصْمَة) is the concept of infallibility or "divinely bestowed freedom from error and sin" in Islam. Muslims believe that Muhammad and other prophets in Islam possessed ‘iṣmah. Twelver and Ismaili Shia Muslims also attribute the quality to Imāms and Fatima Zahra, daughter of Muhammad. Zaidi Shia however, do not attribute ‘ismah to the Imāms.
The concept that Islam had a sinless messenger arises from the Quran. It clearly stated in the first four verse of the 53rd Chapter. The verses clearly state that the prophet does not lie nor is he led astray. The third verse states that he never speaks out of his own inclination. The fourth verse states that what ever he speaks is inspired from God.
The doctrine has been rejected by some, such as the Kharijites, who point to the second ayah in the Surah of Al-Fath, in which God says to Muhammad that he will; "forgive thee thy faults of the past and those to follow". The Qur'an further states that Muhammad's words are only true and infallible insofar as they communicate the Qur'an itself, and that outside the Qur'an, Muhammad's words may be at fault.
Shia Islam 
According to Twelver Shīa, the Fourteen Infallibles (Arabic: معصومون Ma‘ṣūmūn) are historical figures who are infallible which means "divinely bestowed freedom from error and sin" in Islam. The Twelver Shīa believe that Muhammad, his daughter Fatima Zahra, and the Twelve Imams are infallible.
According to Shīa theologians, infallibility is considered a rational necessary precondition for spiritual and religious guidance. They argue that since God has commanded absolute obedience from these figures they must only order that which is right. The state of infallibility is based on the Shīa interpretation of verse of purification.[Quran 33:33] Thus they are, the most pure ones, the only immaculate ones preserved from, and immune to, all uncleanness. It doesn't mean that supernatural powers prevent them from committing a sin, but it is due to the fact that they have absolute belief in God so that they find themselves in presence of God. They have also complete knowledge about God's will. They are in possession of all the knowledge brought by the angels to the prophets (nabi) and the messengers (Rasul). Their knowledge encompasses the totality of all times. Thus they act without fault in religious matters.
The ascription of infallibility to the Imāms is encountered as early as the first half of the 8th century, second century of Islamic calendar, and it was soon extended to the prophets. The doctrine came to exclude the commission on their part of any sin or inadvertence, either before or after their assumption of office. As for Fāṭimah, her infallibility derives from her being a link between prophethood and Imāmah, the two institutions characterized by infallibility, as well as by her association with the Imams and their attributes in numerous traditions. There is general agreement among Twelver Shī‘ah authorities that all fourteen are superior to the rest of creation, including even the major prophets.
Khomeini's interpretation 
A more recent and very influential Shī‘ah interpretation of ‘iṣmah by Ruhollah Khomeini holds that truly faithful and pious Muslims — not just prophets and imams — could possess ‘iṣmah because it could be created by "nothing other than perfect faith." He preached that
infallibility is borne by faith. If one has faith in God, and if one sees God with the eyes of his heart, like sun, it would be impossible for him to commit a sin. .... In front of an armed powerful [master], infallibility is attained.
Scholar Hamid Dabashi argues Khomeini's theory of ‘iṣmah from faith was connected to his theory of Islamic government by guardianship of the jurist. If the truly faithful possessed Ismah, and if Khomeini and the most learned and pious Islamic jurists were truly faithful, than this would reassure Shia hesitant about granting the same ruling authority to Khomeini and his successors, that Shia traditionally believed was reserved for the 12th Imam (Mahdi) on his return. According to Dabashi, Khomeini's theory helped "to secure the all-important attribute of infallibility for himself as a member of the awliyah "friends of God" by eliminating the simultaneous theological and Imamological problems of violating the immanent expectation of the Mahdi."
See also 
- Dabashi, Hamid; Theology of Discontent: The Ideological Foundation of the Islamic Revolution in Iran, 2006, Publisher:Transaction Publishers, ISBN 1-4128-0516-3
- Encyclopædia Iranica. Center for Iranian Studies, Columbia University. ISBN 1-56859-050-4.
- Corbin, Henry (1993 (original French 1964)). History of Islamic Philosophy, Translated by Liadain Sherrard, Philip Sherrard. London; Kegan Paul International in association with Islamic Publications for The Institute of Ismaili Studies. ISBN 0-7103-0416-1.
- Dabashi, Hamid (2006). Theology of Discontent: The Ideological Foundation of the Islamic Revolution in Iran. Transaction Publishers. ISBN 1-4128-0516-3.
- Momen, Moojan (1985). TAn Introduction to Shi`i Islam: The History and Doctrines of Twelve. Yale University Press. ISBN 0-300-03531-4.
- Dabashi, Theology of Discontent, p.463
- Baydawi, Abdullah. "Tawali' al- Anwar min Matali' al-Anzar", circa 1300. Translated alongside other texts in the 2001 "Nature, Man and God in Medieval Islam" by Edwin Elliott Calverley and James Wilson Pollock. pp. 1001-1009
- Dabashi (2006), p.463
- Momen (1985), p.155
- Corbin (1993), pp.48 and 49
- Corbin (1993), p.48
- Algar, Hamid. "Chahardah M'asum". Encyclopedia Iranica. Retrieved 2008-07-18.
- Dabashi, Theology of Discontent, p.463 quoting Khomeini, Jehad-e Akbar (Greater Jihad), pp.44
- Khomeini, Jehad-e Akbar (Greater Jihad), pp.44; Islam and Revolution, p.353
- Dabashi, Theology of Discontent, p.465
- Ayatollah Khomeini's Gems of Islamism, Lectures on the Supreme Jihad, (1972)