Musannaf Ibn Abi Shayba 21:137

Waki’ narrated to us, from Sufyan, from Abu Ishaq, from ‘Asim ibn Damrah, that ‘Ali used to say: "O Allah, Your light was completed, so You guided, and to You is the praise. Your forbearance became great, so You pardoned, and to You is the praise. You extended Your hand, so You gave, and to You is the praise. Our Lord, Your Face is the most noble of faces, Your status is the best of statuses, and Your gift is the most excellent of gifts and the most wholesome. You are obeyed, our Lord, so You are grateful; and You are disobeyed, our Lord, so You forgive. You answer the distressed, remove harm, heal the sick, save from affliction, accept repentance, and forgive the sin of whom You will. No one can recompense Your favors, and no speaker can enumerate Your blessings." He means: he says this after the prayer.