There is a passage in the epistle to the Romans which states that the provision of redemption in Christ Jesus, and the setting forth of Christ to be a propitiation, is emphatically something which shows God to be just, as well as the justifier of those that believe in Jesus. Two comments on this passage are as follows.
In The Apostles’ Doctrine of the Atonement, George Smeaton says this.
“The allusion is to the concurrence or harmony of these two attributes of God. The word just, applied to God, means that he asserts just claims and inflicts just punishment. …
This determines the character of the atonement. Such language would be unmeaning, if it were not admitted that the atonement is in the proper sense of the word a satisfaction of divine justice. … And when the apostle adds, ‘that he might be just, and the justifier,’ he alludes to the fact that these two apparently conflicting perfections, justice and grace, meet in full harmony on the cross: justice suffers no violence, and grace has full outlet.”
Matthew Henry in his Commentary says this.
“He declares his righteousness, first, in the propitiation itself. It appears [or is made apparent] that he hates sin, when nothing less than the blood of Christ would satisfy for it. Finding sin, though but imputed, upon his own Son, he did not spare him, because he had made himself sin for us. Secondly, [he declares his righteousness] in the pardon upon that propitiation. It is now become not only an act of grace and mercy, but an act of righteousness, in God, to pardon the sins of penitent believers, having accepted the satisfaction that Christ by dying made to his justice for them. He is just, that is, faithful to his word.”
Two things need to be borne in mind in considering God’s justice in the scheme of vicarious atonement. One is what the puritans spoke of as the exceeding sinfulness of sin, which the whole discussion makes no sense without. The other is the concept of imputation, and the reality of the transaction that that term describes. Neither of which I’m in a position to develop right now, but it’s worth putting the markers down.
NB: I’m unlikely to be back online now until Wednesday at the earliest. Feel free to carry on, but I might not read it till Thursday.