At the heart of the gospel is a double imputation: my
sin is imputed to Jesus. His righteousness is imputed to me. And in this twofold transaction, we see that
God, who does not negotiate sin, who doesn’t compromise His own integrity with our salvation
but rather punishes sin fully and really after it has been imputed to Jesus, retains His
own righteousness. And so, He is both just and the justifier,
as the Apostle tells us here. So my sin goes to Jesus; His righteousness
comes to me in the sight of God.