Musannaf Ibn Abi Shayba 17:1180

Abu Bakr narrated to us, he said: Abu Usama narrated to us, from Awf, from Ziyad ibn Mikhraq, from Abu Kinana, from Abu Musa, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The son of a people's sister is from among themselves."