Musnad Abu Ya'la al-Mawsili 159:30

Abu Khaythama narrated to us, Sufyan narrated to us, from Abu al-Zinad, from al-A'raj, from Abu Hurayrah, from the Prophet (may Allah bless him and grant him peace), who said: "Satan ties three knots upon the nape of the neck of one of you. If he wakes up and remembers Allah, one knot is untied. If he performs ablution, two knots are untied. If he prays, the knots are untied. Otherwise, he wakes up foul-spirited and lazy."