Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: "We used to recognise the Messenger of Allah (peace and blessings be upon him) concluding the prayer with the salam by this supplication: 'Glorified is your Lord, the Lord of Might, above what they describe; and peace be upon the Messengers; and all praise is for Allah, the Lord of all the worlds.'"
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11175