Chapter 1: The Book of the Sunnah
It was narrated that Abu Hurairah said: "The Messenger of Allah said: 'Learn the Qur' an, recite it and go to bed, for the likeness of the Qur' an and the one who learns it and acts upon it is that of a sack filled with musk, which spreads its fragrance everywhere. And the likeness of one who learns it then goes to bed with it in his heart is that of a sack that is tied up from which no fragrance comes out.'"
Sunan Ibn Majah 217