Chapter 5: Lord's Day 5
Section 12. Q. 12: According to God's righteous judgment we deserve punishment both now and in eternity: how then can we escape this punishment and return to God's favor? A. God requires that his justice be satisfied. Therefore the claims of this justice must be paid in full, either by ourselves or by another.
Section 13. Q. 13: Can we make this payment ourselves? A. Certainly not. Actually, we increase our debt every day.
Section 14. Q. 14: Can another creature — any one at all — pay this debt for us? A. No. To begin with, God will not punish another creature for what a human is guilty of. Furthermore, no mere creature can bear the weight of God's eternal wrath against sin and release others from it.
Section 15. Q. 15: What kind of mediator and deliverer should we look for then? A. One who is truly human and truly righteous, yet more powerful than all creatures, that is, one who is also truly God.