Acts 21:20-21

20 On hearing it, they praised God; but they also said to him, "You see, brother, how many tens of thousands of believers there are among the Judeans, and they are all zealots for the Torah.

21 Now what they have been told about you is that you are teaching all the Jews living among the Goyim to apostatize from Moshe, telling them not to have a b'rit-milah for their sons and not to follow the traditions.