English translation
1608. It was narrated that Abû Hurairah said: "The Messenger of Allâh ﷺ said: 'When any one of you goes to sleep, the Shaiṭân ties three knots on his head, saying each time: "(Sleep) a long night." If he wakes up and remembers Allâh, one knot is undone. If he performs Wudû, another knot is undone. If he prays, all the knots are undone and he starts his day in a good mood and feeling energetic. Otherwise he starts his day in a bad mood and feeling lethargic.'" (Sahîh)
