Romans 3:25-26

God presented Him as a sacrifice of atonement [Or as the one who would turn aside His wrath, taking away sin], through faith in His blood. He did this to demonstrate His justice, because in His forbearance He had left the sins committed beforehand unpunished--He did it to demonstrate His justice at the present time, so as to be just and the One who justifies those who have faith in Jesus.

God punished Christ to demonstrate His justice, having, in forbearance, delayed or held back His wrath for this particular moment. God is just and the One Who justifies believers. Paul says something that should astonish us. God’s mercy towards us in Christ’s subsitutionary, atoning, propitiatory sacrifice, is rooted in God’s justice in Christ’s subsitutionary, atoning, propitiatory sacrifice. Apart from the gospel, Paul says, the validity of the Old Testament sacrificial system is called into question. It would have been immoral and unrighteous for God to institute a system establishing atonement and reconciliation based on the sacrifice of animals, because Scripture says it is and always was impossible for the blood of bulls and goats to take away sins. They were neither able to nor designed to forgive sins. So the Old Testament, as Hebrews declares, was always pointing to the sacrifice that actually could and actually would take away sins, the sacrifice of Christ. And that teaches us that Christ’s cross-work flows both backwards and forward in time. It is Christ’s cross-work that provides the covering for the sins of all those who were under God’s covenant of grace in the Old Testament. And that’s why it was just for God to be merciful to them, even though at that time in history no real sacrifice for sin had been provided. And so also it flows forward to us. We live 2000 years after His crucifixion, after His atoning work, and yet His benefits continue to flow forward.

Justification shows us how God’s mercy is grounded in justice and righteousness. Justification doesn’t compromise His justice or His mercy; it exalts both. Any presentation of the gospel that denies either God’s justice or His mercy is not the gospel. Both of those components must be present in a true presentation of the gospel. That’s the glory of the gospel; it doesn’t compromise the character of God. That’s what makes God both just and the One Who justifies. And who does He justify? The believer is justified, the one who has faith. All those things we talked about—justification, redemption, propitiation, atonement, and substitution—all those things are transferred through the channel of faith.

It’s important to understand that justification has to do with God, not the guilty party. It’s not in the hands of the guilty party to be made just or not. It’s in the hands of the judge. God is the judge, the One Who justifies. And if He justifies someone in His High and Supreme Court, He cannot righteously require a penalty from that person who has been made just. Remember Roman 8:29-30: Those who are justified are also glorified. There’s no turning back. And this gives great assurance of salvation to the believer.

God’s righteousness and justice was at stake in justification. God would have been unrighteous if He passed over sin without saving us in a way that demonstrates His infinite passion for His glory—which is His righteousness. But what we see is that: (1) God’s glory is upheld; (2) His wrath is propitiated; (3) the ransom is paid; (4) His righteousness is demonstrated. Praise Him!