Sahih Muslim Book 35, Hadith Number 6556.
Chapter : Supplication at the time of sleeping and going to bed.
Anas reported Allah’s Messenger (may peace be upon him) as saying: When you go to bed, say: “Praise is due to Allah Who fed us, provided us drink, sufficed us and provided us with shelter, for many a people there is none to suffice and none to provide shelter.”