‏الصلاة : Hadeeth No:757 A hadith like it has been narrated by Abu Huraira but for these words:" He (the man saying the prayer) does not know how much he has prayed....

‏الجهاد والسير‏ : Hadeeth No:4407 The same tradition has been narrated through a different chain of transmitters on the authority of A'mash. This version contains the words: Ila amrin yofzi'una instead of Ila amrin na'rifuhu....