“Shall not the Judge of all the earth do what is just?”
Genesis 18:25

The justice of God consists in the fact that God will give to each person what they merit, either punishment or reward. He treats every person fairly by giving them what they deserve. When God entered into a covenant with Adam, he gave Adam the ability to obey the requirement of perfect obedience in order to merit life as a reward for himself and his posterity. God warned Adam that if he disobeyed, he would be punished with death. When Adam sinned, God justly gave Adam what he deserved. The Shorter Catechism explains that because of Adam’s sin “all mankind lost communion with God, are under his wrath and curse, and are made liable to all the miseries in this life, to death itself, and to the pains of hell forever.”

While it would have been perfectly just of God to allow humanity to reap the punishment of Adam’s disobedience, in love he sent Christ, the Second Adam, to bear the punishment for his elect. Christ bore God’s just condemnation for our sin. “He was pierced for our transgressions; he was crushed for our iniquities” (Isaiah 53:5). God did not compromise his justice by simply overlooking sin, but put forward his only Son, who willingly bore the sins of his people.

Through his perfect obedience, Christ also earned heaven for us. When we put our faith in him, we are united to the one who bore the punishment we deserved, and who earned the eternal life that we could never attain in our fallen state.

This is why the Apostle Paul explains that God is both “just and the justifier of the one who has faith in Jesus” (Romans 3:26). The cross is the greatest demonstration of God’s justice and love. At the cross, justice and mercy kiss (Psalm 85:10). It is in Christ then that we “have redemption through his blood, the forgiveness of our trespasses, according to the riches of his grace” (Ephesians 1:7).

According to God’s justice, we who live by faith in Christ will get the rewards that we deserve on the Last Day, not because we earned them, but because we are united to Christ, the Second Adam. The terrors of the Law and a holy God that will sadly befall those who reject Christ will not befall us because our Savior’s obedience and blood hide all our transgressions from view. Matthew Barrett writes, “The Judge of all the earth always does what is right. In the midst of a world that is wicked and evil and overlooks crimes and the innocent, we can take great comfort knowing that our God is just, and one day he will make all things right. Until that day of final judgment, we point the unjustified to the cross, for there and there only will they find peace with a holy God of love” (None Greater, p. 228).