It wasnarrated that 'Aishah said:
"The Prophet (ﷺ) said: 'Ifanyoneof you becomes drowsy, let him sleep until he feels refreshed,for hedoes not know, if he prays when he feels drowsy, he may want tosaywords seeking forgiveness but (instead) he ends up cursinghimself.'" (FR)
English reference (FR): Vol. 1, Book 5, Hadith 1370 (FR)
Arabic reference (FR): Book 5, Hadith 1432 (FR)