Matthew 18:15-18

If your brother wrongs you, go and show him his fault, between you and him privately. If he listens to you, you have won back your brother. But if he does not listen, take along with you one or two others, so that every word may be confirmed and upheld by the testimony of two or three witnesses. If he pays no attention to them [refusing to listen and obey], tell it to the church; and if he refuses to listen even to the church, let him be to you as a pagan and a tax collector. [Lev. 19:17; Deut. 19:15.] Truly I tell you, whatever you forbid and declare to be improper and unlawful on earth must be what is already forbidden in heaven, and whatever you permit and declare proper and lawful on earth must be what is already permitted in heaven.