The Love and Justice of God

Wayne Grudem:

What was the ultimate cause that led to Christ’s coming to earth and dying for our sins? To find this we must trace the question back to something in the character of God himself. And here Scripture points to two things: the love and justice of God.

The love of God as a cause of the atonement is seen in the most familiar passage in the Bible: “For God so loved the world that he gave his only Son, that whoever believes in him should not perish but have eternal life” (John 3:16). But the justice of God also required that God find a way that the penalty due to us for our sins would be paid (for he could not accept us into fellowship with himself unless the penalty was paid).

Paul explains that this was why God sent Christ to be a “propitiation” (Rom. 3:25 NASB) (that is, a sacrifice that bears God’s wrath so that God becomes “propitious” or favorably disposed toward us): it was “to show God’s righteousness, because in his divine forbearance he had passed over former sins” (Rom. 3:25). Here Paul says that God had been forgiving sins in the Old Testament but no penalty had been paid — a fact that would make people wonder whether God was indeed just and ask how he could forgive sins without a penalty. No God who was truly just could do that, could he? Yet when God sent Christ to die and pay the penalty for our sins, “it was to prove at the present time that he himself is righteous and that he justifies him who has faith in Jesus” (Rom. 3:26).

Therefore both the love and the justice of God were the ultimate cause of the atonement. It is not helpful for us to ask which is more important, however, because without the love of God, he would never have taken any steps to redeem us, yet without the justice of God, the specific requirement that Christ should earn our salvation by dying for our sins would not have been met. Both the love and the justice of God were equally important. (Systematic Theology)