Matthew 18:15-17

“If your brother sins, go and show him his fault when the two of you are alone. If he listens to you, you have regained your brother. But if he does not listen, take one or two others with you, so that at the testimony of two or three witnesses every matter may be established . If he refuses to listen to them, tell it to the church. If he refuses to listen to the church, treat him like a Gentile or a tax collector.