What is to be said at the time of Sleeping
Al-Bara' bin 'Azib (May Allah be pleased with them) reported: Messenger of Allah صلى الله عليه وسلم directed me thus: *"Whenever you go to bed, perform Wudu' as you do for Salat then (before sleeping) recite: Allahumma aslamtu nafsi ilaika, wa wajjahtu wajhi ilaika, wa fawwadtu amri ilaika, wa 'alja'tu zahri ilaika, raghbatan wa rahbatan ilaika, la malja'a wa la manja illa ilaika. Amantu bikitabikal-ladhi anzalta, wa nabiyyikal-ladhi arsalta [O Allah! I have submitted myself to You, I have turned my face to You, committed my affairs to You, and depend on You for protection out of desire for You and out of fear of You (expecting Your reward and fearing Your punishment). There is no refuge and no place of safety from You but with You. I believed in the Book You have revealed, and in the Prophet You have sent (i.e., Muhammad صلى الله عليه وسلم).]''* Messenger of Allah صلى الله عليه وسلم added: *"If anyone recites these words and dies during the night, he will die on the true Deen, and if he remains alive till the morning, he will obtain good. And make this supplication your last words (before sleeping).''*
[Al-Bukhari and Muslim].