Maʿānī al-ʾAkhbār, no. 598

1. We were told by Ahmad bin Ziyad bin Ja’far al-Hamdani, may Allah be pleased with him, that he said: We were told by Ali ibn Ibrahim bin Hashim, from his father, from Muhammed bin Abi ‘Umayr, from Amru bin Jumay’, that he said: Abu Abdillah, peace be upon him, said: There is no harm in performing iq’a’ during prayer between the two prostrations, between the first and second rak’a and between the third and fourth rak’a. If the leader (in prayer) makes you sit in a place in which you must stand in, then withdraw from it. It is not permissible to perform iq’a’ in the place of the (reciting of the) two testimonies, except if due to an illness, because the one who performs iq’a’ is not (legally defined as) sitting, but he would only have sat with some part of himself on another part. Iq’a’ is that a man places his buttocks on his heel bones during his (reciting of the) testification.