سنن ابن ماجه

It was narrated from ‘Ali that whenever the Prophet (ﷺ) prostrated he would say: “Allahumma laka sajadtu, wa bika amantu, wa laka aslamtu, Anta rabbi, sajada wajhi lilladhi shaqqa sam’ahu wa basarahu, tabarak Allah ahsanul-khaliqin (O Allah, to You I have prostrated, and in You I have believed, and to You I have submitted. You are my Lord; my face has prostrated to the One Who gave it hearing and sight. Blessed is Allah the best of Creators).”