Narrated Ibn Mas'ud (RA): Allah's Messenger ( صلی اللہ علیہ وسلم ) offered prayer and when he said Taslim (salutation), he was asked, "O Allah's Messenger! Has something new happened to the Salat (prayer)?" He asked, "What is that?" They said, "You have prayed so many and so many (Rak'at)." He [Ibn Mas'ud (RA)] said, "He then bent his legs, faced the Qiblab, and made two prostrations and then said the Taslim (salutations). Then he faced us and said, "If something new is introduced to the Salat (prayer), I shall inform you but I am a human being like you, I forget just as you forget; so if I forget remind me and if any of you is in doubt about his Salat (prayer) he should act upon what he thinks is correct and complete his prayer in that respect and then he should make two prostrations." [Agreed upon] . And in the narration of al-Bukhari: 'he should complete (the prayer) then he should say Taslim and then perform the prostration'. And in the narration of Muslim: 'the Prophet ( صلی اللہ علیہ وسلم ) performed two Sajdatus-Sabw after Taslim and talking'. In the narration of Ahmad, Abu Dawud and an-Nasa'i from the Hadith of 'Abdullah bin Ja'far (RA) Marfu' [attributed to the Prophet( صلی اللہ علیہ وسلم )] : 'Whoever doubts about his Salat (prayer), should make two prostrations after the Taslim (salutations).' [Ibn Khuzaimah graded it Sahib (authentic)] .