“And he took a cup, and when he had given thanks he gave it to them, saying, ‘Drink of it, all of you, 28 for this is my blood of the covenant, which is poured out for many for the forgiveness of sins.’” (Matthew 26:27–28 ESV).
“Forgiveness assumes grace. If I am injured by you, grace lets it go. I don’t sue you. I forgive you. Grace gives what someone doesn’t deserve. That’s why forgiveness has the word give in it. Forgiveness is not “getting” even. It is giving away the right to get even. … But this raises a problem…”
(John Piper, Fifty Reasons Why Jesus Came to Die [Wheaton: Crossway, 2006] p. 36-37).
The rest of the above referenced book can be downloaded for free as a PDF. This book makes a great devotional for daily Lenten meditations.