Ja'far Sobhani, a Shi‘ite scholar, claimed that the concept of Ismah originated from the Qur’an, regarding the prophet (), angels (66: 6), and the Qur'an itself (41: 42) Dwight M. Donaldson regards the origin and importance of the concept of Ismah owes to the development of the theology of the Shi'ites in the period between the death of Muhammad and the disappearance of the Twelfth Imam.Ann Lambton claims that neither the term nor the concept of Ismah is found in either the Qur'an or in the canonical Sunni hadith. It was apparently first used by the Imamiyyah, perhaps around the beginning of the second century AH, to maintain that the Imam must be immune from sin (ma'sum). Hamid Algar states that the ascription of infallibility to the Imams is encountered as early as the first half of the 8th century, second century AH, and it was soon extended to the prophets. The doctrine came to exclude the commission of any sin or inadvertence on their part, either before or after their assumption of office.