The Book Pertaining to the Remembrance of Allah, Supplication, Repentance and Seeking Forgiveness (Kitab Al-Dhikr)
Muslim :: Book 35 : Hadith 6551
Suhail reported that Abu Salih used to command us (in these words): When any one of you intends to go to sleep, he should lie on the bed on his right side and then say:" O Allah. the Lord of the Heavens and the Lord of the Earth and Lord of the Magnificent Throne, our Lord, and the Lord of evervthina, the Splitter of the grain of corn and the datestone (or fruit kernal), the Revealer of Torah and Injil (Bible) and Criterion (the Holy Qur'an), I seek refuge in Thee from the evil of every- thing Thou art to sieze by the forelock (Thou hast perfect control over it). O Allah, Thou art the First, there is naught before Thee, and Thou art the Last and there is naught after Thee, and Thou art Evident and there is nothing above Thee, and Thou art Innermost and there is nothing beyond Thee. Remove the burden of debt from us and relieve us from want." Abu Salih used to narrate it from Abu Huraira who narrated it from Allah's Apostle (may peace be upon him).