Allah's Apostle said, During your sleep, Satan knots three knots at ...

Hadith 4:491

Narrated Abu Huraira:

Allah's Apostle said, "During your sleep, Satan knots three knots at the back of the head of each of you, and he breathes the following words at each knot, 'The night is, long, so keep on sleeping,' If that person wakes up and celebrates the praises of Allah, then one knot is undone, and when he performs ablution the second knot is undone, and when he prays, all the knots are undone, and he gets up in the morning lively and gay, otherwise he gets up dull and gloomy. "