Romans 3:26

To declare . . . at this time--now for the first time, under the Gospel. his righteousness: that he might be just, and the justifier of him that believeth in Jesus--Glorious paradox! "Just in punishing," and "merciful in pardoning," men can understand; but "just in justifying the guilty," startles them. But the propitiation through faith in Christ's blood resolves the paradox and harmonizes the discordant elements. For in that "God hath made Him to be sin for us who knew no sin," justice has full satisfaction; and in that "we are made the righteousness of God in Him," mercy has her heart's delight! Note, (1) One way of a sinner's justification is taught in the Old Testament and in the New alike: only more dimly during the twilight of Revelation; in unclouded light under "its perfect day" (Rom 3:21). (2) As there is no difference in the need, so is there none in the liberty to appropriate the provided salvation. The best need to be saved by faith in Jesus Christ; and the worst only need that. On this common ground all saved sinners meet here, and will stand for ever (Rom 3:22-24). (3) It is on the atoning blood of Christ, as the one propitiatory sacrifice which God hath set forth to the eye of the guilty, that the faith of the convinced and trembling sinner fastens for deliverance from wrath.

— Jamieson-Fausset-Brown Commentary (public domain)