And he began to teach them that the Son of Man must suffer many things and be rejected by the elders and the chief priests and the scribes and be killed, and after three days rise again.
(Mark 8:31 ESV)
If we know that forgiveness always entails suffering for the forgiver and that the only hope of rectifying and righting wrongs comes by paying the cost of suffering, then it should not surprise us when God says, “The only way I can forgive the sins of the human race is to suffer-either you will have to pay the penalty for sin or I will.” Sin always entails a penalty. Guilt can’t be death with unless someone pays.
The only way God can pardon us and not judge us is to go to the cross and absorb it into himself. “I must suffer,” Jesus said.
-Timothy Keller, King’s Cross, p.101,