There is a hymn that says, “What can wash away my sin, nothing but the blood of Jesus.” Why is that? Why can only Jesus’ blood satisfy the demands of God’s justice and and at the same time show us mercy. There are three options for the removal of our sins. First, we could satisfy for our own sins. Second, another creature could satisfy for our sins. Finally, Jesus could satisfy.  Why can I not atone for my own sins? Why could the bulls and goats in the Old Testament not take away my sins? Why is Jesus the only option?

The Heidelberg Catechism gives an answer to this in questions 12-15.

Q: 12. Since then, by the righteous judgment of God, we deserve temporal and eternal punishment, is there no way by which we may escape that punishment, and be again received into favor? A: God will have his justice satisfied and therefore we must make this full satisfaction, either by ourselves, or by another.

Q: 13. Can we ourselves then make this satisfaction?A: By no means; but on the contrary we daily increase our debt.

Q: 14. Can there be found anywhere, one, who is a mere creature, able to satisfy for us?A: None; for, first, God will not punish any other creature for the sin which man has committed;  and further, no mere creature can sustain the burden of God’s eternal wrath against sin, so as to deliver others from it.

Q: 15. What sort of a mediator and deliverer then must we seek for?A: For one who is very man, and perfectly  righteous;  and yet more powerful than all creatures; that is, one who is also very God.

Question 12 follows up on question 11, which says that God’s mercy does not trump his justice. His justice will be satisfied. Since God’s justice must be satisfied, how can we escape punishment?

Question 13 asks can we atone for ourselves. Is it possible that we can take away our own sin? The answer is no. G.I. Williamson gives a good illustration of why this is the case.

Suppose, for example, that you owed an infinite sum of money-so much money that even the fastest computer could never add it all up. Suppose, too, that you repaid that money at the rate of one thousand dollars a day for one million years. Do you realize that you would still be at the beginning of repayment? The reason is that an infinite sum of money cannot be repaid by any number of finite payments…We have sinned against an infinite God, and there is no way that we can fully repay him by suffering as finite creatures.

Our sins pile up day by day, week by week, month by month, and year by year. But not only do they pile up, but we have sinned against God, not against a creature. The amount of sins and the one we have sinned against mean we cannot now or ever atone for our own sins. This is also why Hell is eternal. We cannot ever atone for our own sins.Having more time does not help when the sins are infinite.

But what about another creature, such as an animal. That is addressed in question 14. There are two reasons why an animal cannot atone. First, a human must atone for the sins of the human race. Second, an animal cannot bear the weight of God’s wrath. Hebrews says, “It is impossible for the blood of bulls and goats to take away sins” (Hebrews 10:4). Animals kept dying day after day, which meant their blood did not atone.

What do we need in order for atonement to happen? We need a true man. Someone who takes on our flesh and blood, a human who will atone for the sins of the human race. But he also must be God because no creature can bear God’s wrath.  That leads directly to question 15. If true atonement is going to happen we need Jesus.

A couple of thoughts follow from this. First, in order for Jesus to atone for our sins, he must be fully God, to bear God’s wrath, and fully man, to take the sins of man upon himself. Without Jesus being fully God and fully man we are still in our sins.

Second, because God’s justice must be satisfied the only options are trusting in Christ or an eternal Hell. There is no third option of our sins be slowly atoned by ourselves in Hell or of God’s justice overlooking sins and annihilating people. Sin must be dealt with. God’s holiness demands justice. Since our sins are against an infinite God only the infinite can bear his wrath. That means Jesus or an infinite time in Hell.

Finally, the glory of Jesus is on full display here. Jesus became the true man (Hebrews 2:14, 17) in order that he might bear the full wrath of God so that those of us who have sinned against God might be delivered from eternal damnation. What a Savior!