Question: "How do Godís mercy and justice work together in salvation?"
Answer: Godís justice and mercy are seemingly incompatible. After all, justice involves the dispensing of deserved punishment for wrongdoing, and mercy is all about pardon and compassion for an offender. However, these two attributes of God do in fact form a unity within His character.
The Bible contains many references to Godís mercy. Over 290 verses in the Old Testament and 70 in the New Testament contain direct statements of the mercy of God toward His people.
God was merciful to the Ninevites who repented at the preaching of Jonah, who described God as ďa gracious and compassionate God, slow to anger and abounding in love, a God who relents from sending calamityĒ (Jonah 4:2). David said God is ďgracious and merciful; Slow to anger and great in loving-kindness. The LORD is good to all, and His mercies are over all His worksĒ (Psalm 145:8–9, NASB).
But the Bible also speaks of Godís justice and His wrath over sin. In fact, Godís perfect justice is a defining characteristic: ďThere is no other God besides me, a just God and a SaviorĒ (Isaiah 45:21, WEB). ďHe is the Rock, his works are perfect, and all his ways are just. A faithful God who does no wrong, upright and just is heĒ (Deuteronomy 32:4).
In the New Testament, Paul details why Godís judgment is coming: ďPut to death, therefore, whatever belongs to your earthly nature: sexual immorality, impurity, lust, evil desires and greed, which is idolatry. Because of these, the wrath of God is comingĒ (Colossians 3:5–6).
So the Bible showcases the fact that God is merciful, but it also reveals that He is just and will one day dispense justice on the sin of the world.
In every other religion in the world that holds to the idea of a supreme deity, that deityís mercy is always exercised at the expense of justice. For example, in Islam, Allah may grant mercy to an individual, but itís done by dismissing the penalties of whatever law has been broken. In other words, the offenderís punishment that was properly due him is brushed aside so that mercy can be extended. Islamís Allah and every other deity in the non-Christian religions set aside the requirements of moral law in order to be merciful. Mercy is seen as at odds with justice. In a sense, in these religions, crime can indeed pay.
If any human judge acted in such a fashion, most people would lodge a major complaint. It is a judgeís responsibility to see that the law is followed and that justice is provided. A judge who ignores the law is betraying his office.
Christianity is unique in that Godís mercy is shown through His justice. There is no setting aside of justice to make room for mercy. The Christian doctrine of penal substitution states that sin and injustice were punished at the cross of Christ, and that only because the penalty of sin was satisfied through Christís sacrifice does God extend His mercy to undeserving sinners who look to Him for salvation.
And while Christ did indeed die for sinners, He also died as a demonstration of Godís righteousness, to showcase His justice. This is exactly what the apostle Paul says: ďAll are justified freely by his grace through the redemption that came by Christ Jesus. God presented Christ as a sacrifice of atonement, through the shedding of his blood—to be received by faith. He did this to demonstrate his righteousness, because in his forbearance he had left the sins committed beforehand unpunished—he did it to demonstrate his righteousness at the present time, so as to be just and the one who justifies those who have faith in Jesus (Romans 3:24–26, emphasis added).
In other words, God didnít immediately punish sin before the time of Christ; rather, extended mercy. But He did not pass over justice. His righteousness (i.e., His justice) was demonstrated by Christís death on the cross. At the cross, Godís justice was meted out in full (upon Christ), and Godís mercy was extended in full (to all who believe). So Godís perfect mercy was and is exercised through His perfect justice.
The end result is that, by the sacrificial death of Jesus, everyone who trusts in Him is saved from Godís wrath and instead experiences His grace and mercy (Romans 8:1). As Paul says, ďSince we have now been justified by his blood, how much more shall we be saved from God's wrath through him!Ē (Romans 5:9).