It is narrated from Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) that when the Messenger of Allah (peace and blessings be upon him) stood for prayer, then he mentioned the complete hadith. In it there is also that when he (peace and blessings be upon him) prostrated, he would recite this supplication in his prostration: 'Allahumma laka sajadtu, wa bika amantu, wa laka aslamtu, wa 'alayka tawakkaltu, sajada wajhi lilladhi khalaqahu wa sawwarahu wa shaqqa sam'ahu wa basarahu, fatabarakAllahu ahsanul-khaliqin' (O Allah, to You alone I have prostrated, in You I have believed, to You I have submitted, and in You I have placed my trust. My face has prostrated to the One who created it and fashioned it, and opened its hearing and its sight. So blessed is Allah, the best of creators).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2684