When we are wronged, our natural reaction is to want retribution. Forgiveness consists of renouncing that very desire…in wishing the wrong-doer well. We have a tradition in Christianity of considering this in terms of transferring this to God: "Vengeance is mine, saith the Lord."
However, God’s forgiveness cannot be less than ours. So if we have renounced any claim to inflict suffering on the culprit, God must have, too.
So where does that leave us? And how do we get justice? Christ’s suffering and death were to appease OUR need for justice, not God’s.
Does that make sense?