´It was narrated that Thawban said:` “I heard the Messenger of Allah (ﷺ) say: ‘For every mistake there are two prostrations, after saying the Salam.’”
Related hadith on this topic
Explanation & Benefits
Maulana Ataullah Sajid
Benefits and Issues:
➊ The meaning of every forgetfulness is that the mistake, whether it is of omission or addition, can be rectified by two prostrations of forgetfulness (sujud as-sahw).
➋ If it becomes certain that fewer units (rak‘ahs) of the prayer have been performed, then the missed rak‘ah should be performed and then the prostration of forgetfulness (sujud as-sahw) should be done, as has been explained in previous chapters.
➌ The prostrations of forgetfulness (sujud as-sahw) can be performed before the salutation (salam) as well as after it. The meaning of the hadith under study is not that sujud as-sahw cannot be done before the salam, but rather that in every case of forgetfulness, it is also correct to perform the prostrations after the salam.
Source: Commentary on Sunan Ibn Mājah by Mawlānā ‘Atā’ullāh Sājid, Page: 1219