Malik, and Abu Hanifah regarding the Imam; because of the saying of the Prophet (peace and blessings of Allah be upon him): "If one of you forgets, let him prostrate twice" (61). And because he has neglected a verbal sunnah, so prostration is legislated for it, like leaving the Qunut. What they mentioned is invalidated by the Qunut and the first tashahhud; for according to Al-Shafi'i, it is a sunnah and the one who leaves it prostrates. So if we say this, [the prostration is recommended], not obligatory. Ahmad stated this clearly. Al-Athram said: I heard Abu Abd Allah being asked about a man who became forgetful and recited aloud in a place where he should have whispered, so are two prostrations of forgetfulness due upon him? He said: As for it being due upon him, I do not say it is due, but if he wishes, he may prostrate. Abu Abd Allah mentioned the hadith from Umar, or someone else, that a humming sound used to be heard from him during the Dhuhr prayer (63). He said: And Anas recited aloud and did not prostrate. And he said: The only forgetfulness for which prostration is required is what has been reported from the Prophet (peace and blessings of Allah be upon him). Salih said: My father said: If he prostrates, there is no harm, and if he does not prostrate, it is not due upon him. And because it is a compensation for something that is not obligatory, so it is not obligatory, like all other sunan.

Section: His statement: "Or he prayed five [rak'ahs]." He means in a four-rak'ah prayer. For whenever he stands up to the fifth in a four-rak'ah prayer, or to the fourth in the Maghrib, or to the third in the Subh, it is incumbent upon him to return whenever he remembers, so he sits. If he had already performed the tashahhud immediately after the rak'ah that completed his prayer, he prostrates for forgetfulness, then performs the taslim (64). If he had performed the tashahhud but had not sent prayers upon the Prophet (peace and blessings of Allah be upon him), he sends prayers upon him, then prostrates for forgetfulness and performs the taslim. And if he had not performed the tashahhud, he performs the tashahhud and prostrates for forgetfulness, then performs the taslim. If he does not remember until he has finished the prayer, he prostrates twice immediately after remembering, performs the tashahhud, and performs the taslim (65), and his prayer is valid. Alqamah, Al-Hasan, Ata',