Musannaf Ibn Abi Shayba 27:745

Waki’ narrated to us, from Sufyan, from Ibn Khuthaym, from Isma’il bin ‘Ubayd bin Rifa’ah, from his father, from his grandfather, who said: The Messenger of Allah (may Allah bless him and grant him peace) gathered Quraysh and said: "Is there among you anyone who is not of you?" They said: "No, except for our sister’s son, our freed slave (mawla), and our ally (halif)." He said: "Your sister’s son is of you, your freed slave is of you, and your ally is of you. Indeed, Quraysh are people of truthfulness and trustworthiness; whoever seeks out their stumbles, Allah will cast him upon his face."