Matthew 18:16-18

18:16 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. 18:17 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.

18:18 “I tell you the truth, whatever you bind on earth will have been bound in heaven, and whatever you release on earth will have been released in heaven.

Matthew 18:20

18:20 For where two or three are assembled in my name, I am there among them.”