Sahih Bukhari
Virtues and Merits of the Prophet (pbuh) and his Companions
Volume: 004 / Book Number: 056 / Hadith Number: 801
Narrated Abu Huraira:
Allah's Apostle said, "This branch from Quraish will ruin the people." The companions of the Prophet asked, "What do you order us to do (then)?" He said, "I would suggest that the people keep away from them.''