Is the latecomer who completed his prayer alone, after the Imam had said the Taslim then returned to complete his prayer, obligated to perform the prostration of forgetfulness (sujud al-sahw), or not? And if he coincides with the Imam who will prostrate for forgetfulness, what should the latecomer do?

A latecomer (Masbuq) has five situations regarding the prostration of forgetfulness (sujud al-sahw):

1. The Imam's forgetfulness, whether the latecomer caught up with it or not: The latecomer is required to perform the prostration of forgetfulness, and the Imam's forgetfulness applies to him. The majority of scholars (Hanafis, Malikis, Shafi'is, Hanbalis) hold this view, with the Malikis adding the condition of having caught up with a full Raka'ah. If the Imam prostrates before the salutation (taslim), the congregant follows him. Shafi'is: The stronger opinion is to repeat the prostration after the latecomer's salutation. Hanbalis: He does not repeat it. If the Imam prostrates after the salutation: The preferred view is that the latecomer does not follow him, and prostrates at the end of his own prayer. Some scholars (such as Ibn 'Uthaymin) are of the opinion that the latecomer does not prostrate if the Imam's forgetfulness occurred before the latecomer joined the prayer.

2. The latecomer's forgetfulness in what he performed alone after the Imam's salutation: He is required to prostrate for his own forgetfulness, as he has become an individual worshipper.

3. The latecomer's forgetfulness in what he performed with the Imam: Shafi'is: The apparent view of the madhhab is that the Imam bears the burden of his forgetfulness. Hanbalis: He is required to prostrate for his own forgetfulness.

4. Both the latecomer and the Imam forgetting: There is a disagreement about whether the latecomer must prostrate for his own forgetfulness after having prostrated with the Imam for the Imam's forgetfulness. Some believe that what he prostrated with the Imam is sufficient.

If the Imam makes a mistake in the number of Raka'ahs (gives the salutation due to a deficiency): The latecomer has the choice of either joining the Imam or completing his prayer individually. He must perform the prostration of forgetfulness in both cases, as he caught up with the Imam in this forgetfulness. If he joins the Imam and the Imam prostrates before the salutation, he prostrates with him. If the Imam prostrates after the salutation, he does not prostrate with him but prostrates at the end of his own prayer. If he chooses to continue alone, he prostrates for forgetfulness at the end of his prayer.

If the latecomer catches up with the Imam in the second prostration of forgetfulness: Hanafis: There is no make-up prostration for him; the second prostration is sufficient. Shafi'is and Hanbalis: He makes up the first prostration after the Imam's salutation. Malikis: If the latecomer did not catch up with a Raka'ah with the Imam, there is no prostration for him, and if he prostrates, his prayer becomes invalid (if the prostration was after the prayer or before catching up with a Raka'ah).