What does justification have to do with the day of judgment? Mark Seifrid answers the question well. “The day of judgment has been brought into the present in Jesus Christ crucified and risen.” It is a piece of the future brought into our present. The cross and resurrection is the courtroom where God condemns and vindicates us in Christ Jesus. Romans 8:31-34 captures this truth best.
“What then shall we say to these things? If God is for us, who can be against us? He who did not spare his own Son but gave him up for us all, how will he not also with him graciously give us all things? Who shall bring any charge against God’s elect? It is God who justifies. Who is to condemn? Christ Jesus is the one who died—more than that, who was raised—who is at the right hand of God, who indeed is interceding for us.”
On the final day no charge will be stand against us according to this text. Why? Because it is God who justifies. Our justification now (Rom 8:1–there is now no condemnation) assures us of our right standing in the future. On that final day who will there be to condemn us? The answer to that is who cares.
The one who ultimately can condemn us will absolutely not condemn us. The one who stands to judge is the one who died, rose, and is interceding for us right now. The one who can condemn us has promised us now that he will never do so. Every accusation of the evil one, of other people, of our consciences, of our sinful deeds will fall impotent before the justifying word of God that has been spoken to us now but keeps us forever.