Jerome
Catena Aurea · Matthäusevangelium 18
Moreover 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. But 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. And 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.
For in saving another, salvation is gained for ourselves also. Chrys What you should do if he does not yield is added, If he will not hear thee, take with thee one or two. For the more shameless and stubborn he shews himself, the more studious should we be of applying the medicine, and not turn to wrath and hate. As the physician, if he see that the disease does not abate, he does not slack, but redoubles his efforts to heal. And observe how this reproof is not for revenge, but for correction, seeing his command is not to take two with him at first, but when he would not amend; and even then he does not send a multitude to him, but one or two, alleging the law, That in the mouth of two or three witnesses every word may stand. (Deut. 19:15.) This is that you may have witnesses that you have done all your part.