Sahih Bukhari
Virtues and Merits of the Prophet (pbuh) and his Companions
Volume: 004 / Book Number: 056 / Hadith Number: 662
Narrated Abu Said:
The Prophet said, "You will follow the wrong ways, of your predecessors so completely and literally that if they should go into the hole of a mastigure, you too will go there." We said, "O Allah's Apostle! Do you mean the Jews and the Christians?" He replied, "Whom else?" (Meaning, of course, the Jews and the Christians.)