It is narrated from Hazrat Abu Hurairah (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: During the night, three knots are tied at the back of the head of the son of Adam. If the servant wakes up and remembers Allah, one knot is untied. If he performs ablution, two knots are untied. And if he offers prayer, all the knots are untied. And if he spends the night without remembering Allah, nor performing ablution and prayer, until morning comes, then he wakes up with all those knots still tied.