He said: "It is permissible for the imam, if he was forgetful and had not reached certainty—until he performed the taslim (salutation) after two rak'ahs because he thought he had completed it—and those behind him performed tasbih and gestured, that he may speak and say: 'Have I reduced my prayer?' This is because his speech at that time—in his own estimation—is after he has finished the prayer, and his action here has become like the action of the Prophet (peace be upon him). Thus, he may complete what remains based on what has passed, provided they have clarified it for him by gesture or tasbih until he reached certainty. If they clarified it for him with speech, while they are certain that he had not completed it, then they must repeat the prayer, because they spoke intentionally during their prayer."

Abu Ya'qub said: "Whoever speaks after the Prophet (peace be upon him) behind an imam in the same manner that Dhu al-Yadayn and his companions spoke, then he must repeat his prayer."

1006 - 'Amr ibn 'Uthman narrated to us, saying: al-Walid ibn Muslim narrated to us, from Abu 'Amr al-Awza'i, who said: "Whoever speaks something in his prayer intentionally, he must repeat his prayer, and whoever speaks out of forgetfulness, there is no repetition upon him."

o I heard Abu Muhammad Harb say: "If a man performs one taslimah, he should not say: 'wa rahmatullah (and the mercy of Allah).""

1007 - 'Amr ibn 'Uthman narrated to us, saying: My father narrated to us, saying: Ibn Lahi'ah narrated to us, from 'Amarah ibn Ghaziyyah and Ibn al-'Ajlan, from Muhammad ibn Yusuf—the freed slave of 'Uthman ibn 'Affan—from his father, that 'Abdullah ibn al-Zubayr joined the prayer having missed some of it. When the imam finished his prayer, he forgot how much he had caught with the imam, so he gestured to the person next to him: 'How much did I catch?' The person did not grasp what he wanted, so he said to him: 'How much did I catch?' He said: 'So and so.' Then he completed the remainder of his prayer.