Matthew 18:15-17 (King James Version)

 ¹⁵Moreover if thy brother shall trespass against thee, go and tell him his fault between thee and him alone: if he shall hear thee, thou hast gained thy brother.

 ¹⁶But if he will not hear thee, then take with thee one or two more, that in the mouth of two or three witnesses every word may be established.

 ¹⁷And if he shall neglect to hear them, tell it unto the church: but if he neglect to hear the church, let him be unto thee as an heathen man and a publican.