(174) باب مَا جَاءَ فِي الرَّجُلِ يُصَلِّي فَيَشُكُّ فِي الزِّيَادَةِ وَالنُّقْصَانِ
Abu Hurairah narrated that:
Allah's Messenger (S) said: "Indeed the Shaitan comes to one of you in his Salat confusing him until he does now know how much he has prayed. When one of you experiences that then let him perform two prostrations while sitting."
Reference: Jami` at-Tirmidhi 397
In-book reference: Book 2, Hadith 250
English translation: Vol. 1, Book 2, Hadith 397