The Oxford Dictionary of the Christian Church defines infallibility as "Inability to err in teaching revealed truth".
According to the First Vatican Council (1869–71) and as reaffirmed at Vatican II (1962–1965), the earthly head of the Catholic Church, the Pope, is infallible when speaking ex cathedra on matters of faith and morals (that is, when he explicitly intends to use his papal office to teach the whole Church definitively and irreformably on matters which deal directly with faith and morals).
[6] This is not the Catholic Church's doctrine, which concedes that Popes can sin and may even contradict one another's personal theological opinions.
It is also held by Shi'as that there were 124,000 Prophets, beginning with Adam and ending with Muhammad - with all, including the last, being infallible in the same sense as the Ahl al-Bayt.
[9][10] The notion of infallibility in Judaism as it relates to the Tannaim and Amoraim of the Talmud, as well as the Rishonim, Achronim and modern day Gedolim is one surrounded by debate.
[citation needed] In the Bhagavad Gita, Krishna explains to Arjuna (Bg 15.16 to 15.20): There are two classes of beings, the fallible and the infallible.
[13]The Baháʼí Faith teaches the doctrine of the Most Great Infallibility (al-'ismah al-kubra) which applies to the Manifestations of God who founded the world's major religions, including Abraham, Krishna, Zoroaster, Moses, Buddha, Jesus Christ, Muhammad, as well as the Báb (1819–1850) and Baháʼu'lláh (1817–1892), the prophet-founder of the faith.
In the Kitáb-i-Aqdas, the central religious text of the faith, Baháʼu'lláh describes himself as having "no partner in the Most Great Infallibility".
In the Will and Testament of ʻAbdu'l-Bahá, he describes both the Guardian and the Universal House of Justice as being "under the care and protection of the Abhá Beauty, under the shelter and unerring guidance of the Exalted One":[15] Whatsoever they decide is of God.