Sahih Bukhari Volume 4, Book 56, Hadith Number 662.

Narated By 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.)