1022 - Al-Walid said: I asked al-Layth ibn Sa'd about that, and he said: "Those whom I encountered among our scholars used to say: They are before the salutation."
Chapter: Regarding someone who missed a rak'ah with the Imam, and then the Imam committed a mistake and added to his prayer; does that suffice for him?
Ishaq ibn Ibrahim was asked about a man who prayed three rak'ahs with the Imam, and one rak'ah had passed him by. When the Imam gave the salutation, this man gave the salutation with him out of forgetfulness. He said: "He should stand up and perform the one rak'ah, and it has sufficed him."
I asked Ishaq, and I said: A man missed one rak'ah of the Dhuhr prayer with the Imam, then the Imam committed a mistake and added a rak'ah to his prayer out of forgetfulness; does this rak'ah which the Imam added suffice for this man in place of the rak'ah that he missed? He said: "If he intends this rak'ah for his obligation, it suffices him." I said: What if he did not intend it? He said: "If he did not intend it for his obligation, it does not suffice him, and he must stand up and perform his obligation."
I asked Ishaq - on another occasion - and I said: A man entered the Dhuhr prayer when the Imam had already preceded him by one rak'ah, so he entered the prayer with the Imam. Then the Imam committed a mistake and prayed five rak'ahs, and this man who had missed a rak'ah prayed them along with him. Does this rak'ah which the Imam added suffice for his missed rak'ah? He said: "If he intends that, it is permissible."
1023 - Ahmad ibn al-Azhar narrated to us, saying: Abu al-Mughirah narrated to us, saying: Al-Awza'i was asked about a man whom the Imam had preceded by one rak'ah, and the Imam committed a mistake and prayed five [rak'ahs]. He said: "The man's prayer is complete, and he should perform the two prostrations of forgetfulness."