Sunan Ibn Majah Book 34, Hadith 51
whenever the Prophet (saas) went to his bed, he would put his hand - meaning his right hand - beneath his cheek then say: "Allahumma qini 'adhabaka yawm tab'athu - - 'ibadaka (O Allah, save me from Your punishment on the Day when You resurrect - or gather - Your slaves)."
the Prophet (saas) said to a man: "When you go to lay down, or go to your bed, say: Allahumma aslamtu wajhi ilayka, wa al-ja'tu zahri ilayka, wa fawwadtu amri ilayka, raghbatan wa rahbatan ilayka, la malja'a wa la manja'a minka illa ilayka, amantu bi kitabikal-ladhi anzalta, wa nabiyyikal arsalta [O Allah, I have submitted my face (i.e., myself) to You, and I am under Your command (i.e., I depend upon You in all my affairs), and I put my trust in You, hoping for Your reward and fearing Your punishment. There is no fleeing from You and no refuge from You except with You. I believe in Your Book that You have revealed and in Your Prophet whom You have sent).' Then if you die that night, you will die in a state of the Fitrah (nature), and if you wake in the morning you will wake with a great deal of good."
“The Messenger of Allah (ﷺ) said: ‘Whoever wakes up in the morning and says upon waking: La ilaha illallah wahdahu la sharika lahu, lahul-mulku wa lahul-hamdu, wa Huwa ‘ala kulli shay’in Qadir; Subhan-Allah walhamdu lillahi, wa la ilaha illallahu, wa Allahu Akbar, wa la hawla wa la quwwata illa billahil-‘Aliyil-‘Azim (None has the right to be worshipped but Allah alone, with no partner or associate. His is the dominion and all praise is to Him, and He is Able to do all things. Glory is to Allah, praise is to Allah, none has the right to be worshiped but Allah, Allah is the Most Great, and there is no power and no strength except with Allah, the Most High, the Most Supreme), then he supplicates Rabbighfirli (O Lord, forgive me), he will be forgiven.’” Walid said: “Or he said: then if he supplicated, it will be answered for him then if he stood up and performed ablution and then performed prayer, his prayer would be accepted.”