Musnad Abu Ya'la al-Mawsili 42:145

Ishaq narrated to us, Hammad narrated to us, from Abu Harun, who said: We said to Abu Sa'id, "Did you memorize anything from the Messenger of Allah, may Allah bless him and grant him peace, that he used to say after he would say the taslim?" He said, "Yes, he used to say: 'Exalted is your Lord, the Lord of might, above what they describe. And peace be upon the messengers. And praise to Allah, Lord of the worlds.'"