Musnad Ahmad 724:2

Waki’ narrated to us, Sufyan narrated to us, from Ibn Khuthaym, from Isma’il ibn ‘Ubayd ibn Rifa’ah, from his father, from his grandfather, who said: The Messenger of Allah, peace and blessings of Allah be upon him, gathered the Quraysh and said: "Is there anyone among you who is not of you?" They said: "No, except for our sister’s son, our ally, and our freedman." He said: "Your sister’s son is of you, your ally is of you, and your freedman is of you. Indeed, the Quraysh are people of truthfulness and trustworthiness. Whoever seeks to cause them stumbling, Allah will cast him into the Fire upon his face."