Answered by Shaykh Sohail Hanif, SunniPath Academy Teacher
This is about performing a “FORGETFULNESS PROSTRATION”, if one misses a wajib part of one’s prayer. if one realizes that he has missed a wajib act, and intends to do a FORGETFULNESS PROSTRATION, but then forgets to do so. what is the ruling ?
Assalamu alaykum
A forgetfulness prostration (sujud al-sahw) is necessitated whenever one omits a necessary (wajib) element of the prayer. Should one fail to prostrate the forgetfulness prostration then one’s prayer remains deficient and it is necessary (wajib) to repeat the prayer.
In the event that one finishes the prayer and then remembers that one was supposed to have performed a forgetfulness prostration one may still perform it provided that one has not spoken with anybody or left one’s place of prayer. In this case one need only perform two prostrations followed by the tashahhud and then give two salams as normal whilst intending that these were forgetfulness prostrations. [Radd al-Muhtar, 1:505, Dar Li Ihya al-Turath al-‘Arabi]