Sunan an-Nasa'i 1238

Yahya ibn Habib ibn ‘Arabi reported to us; he said: Khalid reported to us, from Ibn ‘Ajlan, from Zayd ibn Aslam, from ‘Ata’ ibn Yasar, from Abu Sa‘id, from the Prophet (ﷺ), who said: “If any one of you is uncertain about his prayer, let him set aside the doubt and proceed on the basis of what he is certain of. When he is sure he has completed it, let him prostrate twice while seated. If he has prayed five rak‘ahs, the two prostrations will make his prayer even; if he has prayed four, they will humble Satan.”