Sahih al-Bukhari · Hadith 1232

Forgetfulness in Prayer

Narrated Abu Huraira: Allah's Messenger (ﷺ) said, "When anyone of you stands for the prayers, Satan comes and puts him in doubts till he forgets how many rak`at he has prayed. So if this happens to anyone of you, he should perform two prostrations of Sahu while sitting