Matthew 18:17

AUV(i) 17 And if he refuses to listen to them [i.e., the witnesses], explain the [whole] matter to the church [i.e., probably a specially called meeting of mature Christians to resolve the matter]. And if he refuses to listen to the church also, [i.e., to acknowledge his sin and repent of it], consider him like an [unconverted] Gentile or tax collector [i.e., do not have fellowship with him].