• I also heard Ishaq being asked about a man who forgot a prostration from his prayer. He said: "He should perform it and repeat whatever follows it from the prayer."

1002 - Abu Hisham narrated to us, he said: Hassan ibn Ibrahim narrated to us, from Sufyan, concerning a man who prayed four rak'ahs and did not perform in each rak'ah except one prostration, and he remembered while sitting in the fourth rak'ah. He said: "He performs the prostrations [he missed], one after another, while he is sitting. If he had already performed the tashahhud, he repeats the tashahhud, then performs the two prostrations of forgetfulness after he performs the taslim. If he had spoken before performing the prostrations, he repeats the prayer."

Chapter: The Two Prostrations of Forgetfulness in Supererogatory (Tatawwu') Prayer

• I asked Ahmad ibn Hanbal, saying: "The two prostrations of forgetfulness are in both the obligatory (fard) and supererogatory (tatawwu') prayers?" He said: "Yes."

1003 - Yahya ibn Abd al-Hamid narrated to us, he said: Ibn al-Mubarak narrated to us, from Ya'qub ibn al-Qa'qa', from 'Ata', from Ibn 'Abbas, he said: "If one makes a mistake in a supererogatory prayer, he performs the two prostrations of forgetfulness."

1004 - 'Amr ibn 'Uthman narrated to us, he said: 'Abd Allah ibn Wahb narrated to us, he said: Haywah ibn Shurayh narrated to us, from Zuhrah ibn Ma'bad, from Sa'id ibn al-Musayyib, he said: "The two prostrations of forgetfulness in a supererogatory prayer are like the two prostrations of forgetfulness in the prescribed (maktubah) prayer."