Acts 16:1-10
From there he went to Derbe, and then on to Lystra, where there was a disciple called Timothy, whose mother was Jewish and had become a believer; but his father was a Greek. The brothers at Lystra and Iconium spoke well of him, and Paul, who wanted to have him as a travelling companion, had him circumcised. This was on account of the Jews in the locality where everyone knew his father was a Greek.