كان رسول الله صلى الله عليه وسلم اذا اراد ان ينام قال:(باسمك اللهم أموت واحيا) واذا استيقظ من منامه قال:(الحمد لله الذى احيانا بعد ما اماتنا واليه النشور)

رواه البخارى ومسلم

The messenger of Allah (may the blessings and peace of Allah be upon him),when he wanted to sleep, he would say :In Your name ,O Allah, I die and I live." And when he awoke from his sleep ,he would say:" Thanks be to Allah who has brought us to life   after having us to die, and to Him is the Resurrection."..

Narrated by Al Bukhari and Muslim