Galatians 2:3-5

But not even Titus, who was with me, though he was a Greek, was compelled to be circumcised. But it was because of the false brethren secretly brought in, who had sneaked in to spy out our liberty which we have in Christ Jesus, in order to bring us into bondage. But we did not yield in subjection to them for even an hour, so that the truth of the gospel would remain with you.