Mistake in Ruku‘

“I once asked abu ’Abd Allah (a.s.), about a man who in a standing position doubts and does not know if he has performed Ruku‘ (bowing down on one’s knees) or not. He (the Imam) said, ‘He performs Ruku‘ and Sajdah…

“I once asked abu ‘Abd Allah (a.s.), about a man who forgets performing Ruku‘ (bowing down on one’s knees) until he performs Sajdah (prostration) and stands up. He (the Imam) said, ‘He performs Salah (prayer) again.’”

“Abu Ja‘far (a.s.), has sad, ‘If one is certain that he has increased one Rak‘at in an obligatory Salah (prayer) he disregards it and performs that Salah (prayer) again if he has certainty.’”