It is narrated from Sayyidah Aisha (may Allah be pleased with her) that the Prophet Muhammad (peace and blessings be upon him) said: "When any one of you becomes drowsy during his prayer, he should (end the prayer and) go to sleep until his sleep is over, because when any one of you prays while drowsy, he may intend to seek forgiveness but (due to drowsiness) he might curse himself instead." These are the words of Isa's narration. Imam Abu Bakr (may Allah have mercy on him) says that in this hadith there is evidence that drowsiness does not break the prayer, because if drowsiness broke the prayer, then the statement of the Prophet (peace and blessings be upon him) would have no meaning: "He does not know, perhaps he wants to supplicate and seek forgiveness, but (due to drowsiness) he might curse himself." From this it is understood that the Prophet (peace and blessings be upon him) commanded us to leave the prayer due to the fear that the worshipper might, instead of supplicating, curse himself. It does not mean that when he becomes drowsy, he is no longer in prayer (that his prayer is broken).