Musannaf Ibn Abi Shayba 27:748

Narrated to us Abd al-A’la, from Ma’mar, from al-Zuhri, from Sahl ibn Abi Hathma, that the Messenger of Allah (may Allah bless him and grant him peace) said: "Learn from Quraysh and do not teach them, and put Quraysh forward and do not put them behind. For indeed, the Qurayshi has the strength of two men from other than Quraysh."