The Ruling on the Additions to Prayer and the Latecomer

Question:

If a Muslim arrived while the Imam was praying and he caught the second Rakah with him, but the Imam made a mistake in the prayer and prayed five Rakahs, would his prayer be complete, if he did not make up the Rakahs he missed with the Imam? If the Imam made the prostration of forgetfulness, should he make it with him or not? Please explain the matter, and may Allaah reward you with goodness.

Answer:

There exists a difference of opinion in this matter among the scholars - may Allaah have mercy on them: Some of them hold that the extra Rakah compensates for the latecomer (i.e. for the Rakah which he missed), while some said that it does not, and the correct view is that it does not compensate for it, because compensating for what he has missed in the prayer must be after the Taslim. Therefore, if his Imam makes the Taslim, he should stand up and perform what he has missed, and he should not follow the Imam in performing a fifth Rakah, but should remain sitting until the Imam makes the Taslim, then once the Imam has done so, he may stand up and make up for what is incumbent upon him. Also those whom the Imam leads in prayer (from the beginning) ý they should not perform the fifth Rakah with him, rather they must alert the Imam (to the fact that he is praying an extra Rakah), if he responds to them (and well and good), but if he does not, they must wait for him and not follow him, if they are sure that it is excess. But whoever followed him due to ignorance of the Islamic ruling, or ignorance of the fact that it was excess, his prayer would be correct. And it is upon the latecomer to perform the prostration of forgetfulness with the Imam if he does so. Then when he makes the Taslim, he should stand and make up for what he has missed. And Allaah is the Granter of success.

Source :
Shaykh `Abdul-`Azeez Bin Baz
Fatawa Islamiyah Vol. 2 Page 187