"If your brother or sister sins against you, go and correct them when you are alone together. If they listen to you, then you've won over your brother or sister.
References for Matthew 18:15
But if they won't listen, take with you one or two others so that every word may be established by the mouth of two or three witnesses.
References for Matthew 18:16
But if they still won't pay attention, report it to the church. If they won't pay attention even to the church, treat them as you would a Gentile and tax collector.
I assure you that whatever you fasten on earth will be fastened in heaven. And whatever you loosen on earth will be loosened in heaven.
Again I assure you that if two of you agree on earth about anything you ask, then my Father who is in heaven will do it for you.
For where two or three are gathered in my name, I'm there with them."