Hadith 814 - Bab 127 (What is to be said at the time of Sleeping)
Chapter 5 (The Book of the Etiquitte of Sleeping, Lying and Sitting etc)

Al-Bara' bin 'Azib (May Allah be pleased with them) reported: Whenever Messenger of Allah (Peace be upon him) went to bed, he would lie down on his right side and 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 (Peace be upon him)).]"

[Al-Bukhari].

Hadith 815 - Bab 127 (What is to be said at the time of Sleeping)
Chapter 5 (The Book of the Etiquitte of Sleeping, Lying and Sitting etc)

Al-Bara' bin 'Azib (May Allah be pleased with them) reported: Messenger of Allah (Peace be upon him) directed me thus: "Whenever you go to bed, perform Wudu' as you do for Salat then (before sleeping) recite: 'O Allah! I have submitted myself to You, I have turned myself to You, committed my affairs to You and sought Your refuge for protection out of desire for You and 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 believe in the Book You have revealed and in the Prophet (Peace be upon him) You have sent."' Messenger of Allah (Peace be upon him) 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].

Hadith 816 - Bab 127 (What is to be said at the time of Sleeping)
Chapter 5 (The Book of the Etiquitte of Sleeping, Lying and Sitting etc)

'Aishah (May Allah be pleased with her) reported: The Prophet (Peace be upon him) used to offer eleven Rak'ah of optional Salat (prayers) in the latter part of night. When it was about dawn, he would offer two short Rak'ah and then would lie down on his right side till the Mu'adhdhin (one who calls for prayer) would come to inform him that the congregation had gathered (for prayer).

[Al-Bukhari and Muslim].

Hadith 817 - Bab 127 (What is to be said at the time of Sleeping)
Chapter 5 (The Book of the Etiquitte of Sleeping, Lying and Sitting etc)

Hudhaifah (May Allah be pleased with him) reported: Whenever the Prophet (Peace be upon him) lay down for sleep at night, he would place his (right) hand under his (right) cheek and supplicate: "Allahumma bismika amutu wa ahya [O Allah, with Your Name will I die and live (wake up)]." And when he woke up, he would supplicate: "Al-hamdu lillahil-ladhi ahyana ba'da ma amatana, wa ilaihin-nushur (All praise is due to Allah, Who has brought us back to life after He has caused us to die, and to Him is the return)."

[Al-Bukhari].

Hadith 818 - Bab 127 (What is to be said at the time of Sleeping)
Chapter 5 (The Book of the Etiquitte of Sleeping, Lying and Sitting etc)

Ya'ish bin Tikhfah Al-Ghifari (May Allah be pleased with him) reported: My father said: I was lying down on my belly in the mosque when someone shook me with his foot and said, "Lying down this way is disapproved by Allah." I looked up and saw that it was Messenger of Allah (Peace be upon him).

[Abu Dawud].

Hadith 819 - Bab 127 (What is to be said at the time of Sleeping)
Chapter 5 (The Book of the Etiquitte of Sleeping, Lying and Sitting etc)

Abu Hurairah (May Allah be pleased with him) reported: Messenger of Allah (Peace be upon him) said, "Whoever sits in a place where he does not remember Allah (SWT), he will suffer loss and incur displeasure of Allah; and whoever lies down (to sleep) in a place where he does not remember Allah, he will suffer sorrow and incur displeasure of Allah."

[Abu Dawud].