Mercy is not opposed to justice but rather expresses God’s way of reaching out to the sinner, offering him a new chance to look at himself, convert, and believe.
If God limited himself to only justice, he would cease to be God, and would instead be like human beings who ask merely that the law be respected. But mere justice is not enough. Experience shows that an appeal to justice alone will result in its destruction. This is why God goes beyond justice with his mercy and forgiveness. Yet this does not mean that justice should be devalued or rendered superfluous. On the contrary: anyone who makes a mistake must pay the price. However, this is just the beginning of conversion, not its end, because one begins to feel the tenderness and mercy of God. God does not deny justice. He rather envelopes it and surpasses it with an even greater event in which we experience love as the foundation of true justice.
God’s justice is his mercy given to everyone as a grace that flows from the death and resurrection of Jesus Christ. Thus the Cross of Christ is God’s judgement on all of us and on the whole world, because through it he offers us the certitude of love and new life.