"If your brother sins against you, go and rebuke him in private. If he listens to you, you have won your brother.
References for Matthew 18:15
But if he won't listen, take one or two more with you, so that by the testimony of two or three witnesses every fact may be established.
References for Matthew 18:16
If he pays no attention to them, tell the church. But if he doesn't pay attention even to the church, let him be like an unbeliever and a tax collector to you.
References for Matthew 18:17
I assure you: Whatever you bind on earth is already bound in heaven, and whatever you loose on earth is already loosed in heaven.
References for Matthew 18:18
Again, I assure you: If two of you on earth agree about any matter that you pray for, it will be done for you by My Father in heaven.
References for Matthew 18:19
For where two or three are gathered together in My name, I am there among them."