Oh, it wasn't and isn't a cheap forgiveness. It cost life and it costs lives. Easter is the happy day after a week of sorrow. The lover of God came to us in the sorrow of a human on the cross. That is the way of life.
All spiritual love is born of sorrow.
People love one another and God, after they have suffered the same sorrow together. Christ has suffered with us. Christ has ploughed the stony ground beneath each of us. In our common pain and common joy, we know deeply that each is a child of God. In Christ, has come life.