The second exception: if he is uncertain about an addition while performing it, then it becomes clear that there was no addition, he must perform the prostration, because he performed part of his prayer while uncertain whether it belonged to it. He must therefore prostrate on account of this uncertainty.

“No prostration is required of a follower except in conjunction with his imam.”

His statement, “No prostration is required of a follower except in conjunction with his imam,” means that a follower is not required to perform the prostration for forgetfulness except in following his imam.

Thus, the phrase “no prostration” is general and includes prostration due to uncertainty, due to an addition, or due to an omission.

This is because the Prophet ﷺ said: “The imam has only been appointed to be followed, so do not differ from him” (1). Moreover, the prostration for forgetfulness is obligatory, but not an integral pillar; and an obligation is waived for the follower in order to maintain conformity with the imam. This applies in a number of cases:

Among them: if the imam rises after the first tashahhud, having forgotten it, it is waived for the follower.

Another is when the follower joins the imam in the second rak‘ah of a four-rak‘ah prayer: the first tashahhud is waived for the follower, because for this follower the first tashahhud would fall in the imam’s third rak‘ah. It is known that the imam does not sit in the third rak‘ah, so the follower must rise with him, and thus one of the prayer’s obligations is waived for him. If an obligation is waived for the follower in order to follow the imam, then the prostration for forgetfulness—which is an obligation—is likewise waived for the follower in order to follow him. Based on this reasoning, it is stipulated that he has not missed any part of the prayer.