As for if he precedes him by two rak'ahs, such that he bows before him, then when he intended to bow, he rose, and when he intended to rise, he prostrated intentionally, his prayer is void because he did not follow his Imam in the majority of the rak'ah. If he did this by mistake, his prayer is not void, because he is excused, yet that rak'ah is not counted due to his lack of following his Imam in it.

Section: If the Imam precedes the follower by a complete pillar, such as if he bowed and rose before the follower's bowing due to an excuse such as drowsiness, a crowd, or the Imam's haste, then he performs what he was preceded in and catches up with his Imam, and there is nothing upon him. Ahmad explicitly stated this. Al-Marwudhi said: I said to Abu 'Abd Allah: The Imam, if he prostrates and raises his head before I prostrate? He said: If it is one prostration, then follow him when he raises his head. I do not know of any disagreement regarding this. If he precedes him by a complete rak'ah or more, then he follows his Imam and makes up what the Imam preceded him by. Ahmad said concerning a man who dozed off behind the Imam until he prayed two rak'ahs: It is as if he caught up with two rak'ahs, so when the Imam performs the Taslim, he prays two rak'ahs. If he precedes him by more than one pillar but less than a rak'ah, and then his excuse ceases, the stated position from Ahmad is that he follows his Imam and does not count that rak'ah. He said concerning a man whose Imam bowed and prostrated while he was standing, unaware, and did not bow until the Imam prostrated: He prostrates with him and performs a rak'ah in its place. Al-Marwudhi said: I said to Abu 'Abd Allah, the Imam, if he prostrates and raises his head before I prostrate? He said: If it is one prostration, follow him when he raises his head, and if it is two prostrations, that rak'ah is not counted. The apparent meaning of this is that whenever he precedes him by two rak'ahs, that rak'ah is void. If he precedes him by less than that, he performs it and catches up with his Imam. Our companions said concerning someone who was crowded out from prostrating on the day of Jumu'ah: He waits for the crowd to clear, then he prostrates and follows the Imam, as long as he does not fear missing the bowing in the second [rak'ah] with the Imam. This implies that he performs what he missed even if it is more than one pillar. This is the view of al-Shafi'i, because the Prophet (peace and blessings of Allah be upon him) did this with his companions in the prayer of 'Usfan (14), when...