Abu Dawud Book 36, Hadith Number 5034.

Narated By Ali ibn AbuTalib : The Apostle of Allah (PBUH) used to say when he lay down: O Allah, I seek refuge in Thy noble Person and in Thy perfect Words from the evil of what Thou seizest by its forelock; O Allah! Thou removest debt and sin; O Allah! thy troop’s not routed, Thy promise is not broken and the riches of the rich do not avail against Thee. Glory and praise be unto Thee!.