Musnad Abu Ya'la al-Mawsili 4:24

Abu Bakr ibn Abi Shaybah narrated to us, Muhammad ibn Bishr al-‘Abdi narrated to us, Mujammi‘ ibn Yahya narrated to us, from ‘Uthman ibn Mawhab, from Musa ibn Talhah, from his father, who said: We said, "O Messenger of Allah, we have already learned how to greet you, so how do we send blessings upon you?" He said, "Say: O Allah, send blessings upon Muhammad and upon the family of Muhammad, as You sent blessings upon Ibrahim and upon the family of Ibrahim; indeed, You are Praiseworthy, Glorious. And bless Muhammad and the family of Muhammad, as You blessed Ibrahim and the family of Ibrahim; indeed, You are Praiseworthy, Glorious."