Acts 21:21 (KJV)

And when he had saluted them, he declared particularly what things God had wrought among the Gentiles by his ministry.

And when they heard it, they glorified the Lord, and said unto him, Thou seest, brother, how many thousands of Jews there are which believe; and they are all zealous of the law:

And they are informed of thee, that thou teachest all the Jews which are among the Gentiles to forsake Moses, saying that they ought not to circumcise their children, neither to walk after the customs.

What is it therefore? the multitude must needs come together: for they will hear that thou art come.

Do therefore this that we say to thee: We have four men which have a vow on them;