Acts 16:1-3

Then he came to Derbe and Lystra. And behold, a certain disciple was there, named Timothy, the son of a certain Jewish woman who believed, but his father was Greek. He was well spoken of by the brethren who were at Lystra and Iconium. Paul wanted to have him go on with him. And he took him and circumcised him because of the Jews who were in that region, for they all knew that his father was Greek.