Question: "How do God's mercy and justice work together in salvation?"
Answer: God’s 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 God’s 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 “a gracious and compassionate God, slow to anger and abounding in love, a God who relents from sending calamity” (Jonah 4:2). David said God is “gracious and merciful; Slow to anger and great in loving-kindness. The LORD is good to all, and His mercies are over all His works” (Psalm 145:8–9, NASB).
But the Bible also speaks of God’s justice and His wrath over sin. In fact, God’s perfect justice is a defining characteristic: “There is no God apart from me, a righteous [just] God and a Savior; there is none but me” (Isaiah 45:21). “He is the Rock, his works are perfect, and all his ways are just. A faithful God who does no wrong, upright and just is he” (Deuteronomy 32:4).
In the New Testament, Paul details why God’s judgment is coming: “Put 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 coming” (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 deity’s mercy is always exercised at the expense of justice. For example, in Islam, Allah may grant mercy to an individual, but it’s done by dismissing the penalties of whatever law has been broken. In other words, the offender’s punishment that was properly due him is brushed aside so that mercy can be extended. Islam’s 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 those religions, crime can indeed pay.
If any human judge acted in such a fashion, most people would lodge a major complaint. It is a judge’s 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 God’s 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 it’s only because the penalty of sin was satisfied through Christ’s sacrifice that God extends His mercy to undeserving sinners who look to Him for salvation.
As Christ died for sinners, He also demonstrated God’s righteousness; His death on the cross showcased God’s justice. This is exactly what the apostle Paul says: “All 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, all the sin from Adam to the time of Christ was under the forbearance and mercy of God. God in His mercy chose not to punish sin, which would require an eternity in hell for all sinners, although He would have been perfectly just in doing so. Adam and Eve were not immediately destroyed when they ate the forbidden fruit. Instead, God planned a Redeemer (Genesis 3:15). In His love God sent His own Son (John 3:16). Christ paid for every single sin ever committed; thus, God was just in punishing sin, and He can also justify sinners who receive Christ by faith (Romans 3:26). God’s justice and His mercy were demonstrated by Christ’s death on the cross. At the cross, God’s justice was meted out in full (upon Christ), and God’s mercy was extended in full (to all who believe). So God’s perfect mercy was exercised through His perfect justice.
The end result is that everyone who trusts in the Lord Jesus is saved from God’s wrath and instead experiences His grace and mercy (Romans 8:1). As Paul says, “Since we have now been justified by his blood, how much more shall we be saved from God’s wrath through him!” (Romans 5:9).