Paul teaches that God forgive his enemies for Christ’s sake. This is to say that God’s forgiveness of his enemies is grounded in Christ’s satisfaction for their guilt. It also implies that those enemies of God who reject Christ’s satisfaction are not forgiven by God.
The forgiveness required of us is to be after the pattern of God’s forgiveness. Now, how does God forgive his enemies? He forgives only upon condition of repentance and faith; not otherwise. And Christ, in teaching Peter, shows that our forgiveness is not required to go beyond God’s.
If thy brother “trespass against thee seven times in a day, and seven times in a day turn again to thee, saying, I repent; thou shalt forgive him.” (Luke 17:4.) So what if the offender says, “I do not repent?” Christ answers (in another place), don’t seek revenge, but let him be unto thee as a heathen man and a publican.
So what relation do we stand to our trespassers in this forgiveness of injuries? We are simply fallible creatures, sinners toward God. By comparison, what relation does God stand to his trespassers? He is sovereign owner, infallible chief-justice and magistrate. That makes all the difference. “Vengeance is mine, saith the Lord.”
The visiting of due retribution upon guilt is the exclusive prerogative of God. That’s because his sovereignty, his power, his purity, his infallible wisdom and justice qualify him for that task. Therefore, we who are disqualified are not to meddle with it. Moreover, it is fatuous to infer that because God says we are unfit — and therefore must not meddle with his prerogative — therefore he must not exercise it himself.
Even the poorest human magistrate sees this difference perfectly. Let’s suppose that a thief duly convicted should reason with him to set aside a just verdict in this way: “Your honor, you are a charitable Christian. Last year, when I and my family were in distress, your charity gave me relief. This verdict puts us in distress again. So the same charity should again release us.”
We presume the dullest judge would know to say: “Back then I was acting toward thee as a private person and neighbor. I took what was mine own to help your distress;. Now I sit in the judgment seat; I represent the delegated rights of the law, of eternal justice and of God. These things are not mine to give away as charity. I am sacredly sworn to uphold them. Would it be charity in me to commit theft and perjury to extend relief to you in this present distress, where you deserve none?”
–Modernized from chapter 5 of Dabney’s classic, Christ our Penal Substitute