Answered by Ustadh Tabraze Azam
Question: Assalam alaykum
If a latecomer to the prayer stands up to complete his prayer, for example after the Imam does his first salaam, but then realizes that the Imam later goes on to perform a prostration of forgetfulness (sajda al-sahw), what does the latecomer do? Does he sit back down and follow the Imam?
Answer: Wa alaikum assalam wa rahmatullah,
Yes, if the follower (ma’mum) stands to make up his missed cycles (rak`ats), yet the imam performs the prostrations of forgetfulness (sajda al-sahw), the follower should sit back down again and follow the imam.
The reason for this is that you are only normally separated from the imam when he exits the prayer entirely. But the salam given before the prostrations of forgetfulness is not for exiting, and hence, the follower remains bound by the actions of the imam.
If, however, a person begins to make up the missed cycles without following the imam in the prostration, he would prostrate at the end of his prayer. But this is not the correct response to the situation at hand.
[Shurunbulali, Maraqi al-Falah with Tahtawi’s Gloss (2.64-65); Ibn `Abidin, Radd al-Muhtar `ala al-Durr al-Mukhtar (1.499)]
Please also see: Can the Forgetfulness Prostration Be Done in Every Prayer Just to Be Sure it is Valid? and: Was I Correct to Perform the Forgetfulness Prostrations After Reciting the Opening Supplication in the Third Cycle of Prayer?
And Allah Most High alone knows best.
[Ustadh] Tabraze Azam
Checked and Approved by Shaykh Faraz Rabbani
Ustadh Tabraze Azam holds a BSc in Computer Science from the University of Leicester, where he also served as the President of the Islamic Society. He memorised the entire Qur’an in his hometown of Ipswich at the tender age of sixteen, and has since studied the Islamic Sciences in traditional settings in the UK, Jordan and Turkey. He is currently pursuing advanced studies in Jordan, where he is presently based with his family.