Musnad Abu Ya'la al-Mawsili 117:49

Hadaba narrated to us, Hammad narrated to us, from Thabit, from Anas bin Malik, that the Messenger of Allah (may Allah bless him and grant him peace), when he made peace with Quraysh on the day of al-Hudaybiyah, said to Ali: "Write: In the name of Allah, the Most Gracious, the Most Merciful." Suhayl bin Amr said: "We do not know the Most Gracious, the Most Merciful. Write: In Your name, O Allah." The Messenger of Allah (may Allah bless him and grant him peace) said to Ali: "Write: This is what Muhammad, the Messenger of Allah, has agreed upon." Suhayl bin Amr said: "If we knew that you were the Messenger of Allah, we would have followed you and would not have belied you. Write your lineage from your father." The Prophet (may Allah bless him and grant him peace) said to Ali: "Write: Muhammad bin Abdullah." So he wrote: "Whoever comes to us from you, we will return him to you; and whoever comes to you from us, we will leave him with you." They said: "O Messenger of Allah, will you give them this?" He said: "Whoever comes to them from us, may Allah distance him; and whoever comes to us from them, and we return him to them, Allah will grant him relief and a way out."