Augustine of Hippo
Catena Aurea · Matthäusevangelium 18
Verily I say unto you, Whatsoever ye shall bind on earth shall be bound in heaven: and whatsoever ye shall loose on earth shall be loosed in heaven. Again I say unto you, That if two of you shall agree on earth as touching any thing that they shall ask, it shall be done for them of my Father which is in heaven. For where two or three are gathered together in my name, there am I in the midst of them.
(ubi sup.) Otherwise; When you begin to hold your brother as a publican you bind him on earth, but take heed that you bind him with just cause; for an unjust cause breaks rightful bonds. But when you have corrected him, and agreed with him, you have loosed him upon earth, and when you have loosed him upon earth, he shall be loosed also in heaven. You confer a great boon not on yourself, but on him, as he had done the hurt not to you but to himself.