In Genesis 22 God (through Moses) has given us a history of his command to Abraham to take Isaac up a mountain and sacrifice him. The text itself tells us why and as you read through the account you quickly realize that God spared the life of Isaac and provided a substitution for his sacrifice. As we look at this passage on Sunday we are going to find there is more than one reason for the sparing of Isaac's life. In fact, we find it was always God's intention to spare Isaac's life for the sake of affirming Abraham's faith. It does, however, provoke us to consider why Isaac could never have been an appropriate sacrifice.
Isaac had a unique position in the world. He was God's immediate son of promise given to Abraham. Through Isaac all of God's covenant promises made to Abraham would be kept alive. That doesn't mean that Isaac was in any way sinless. By the end of chapter 22, one clear and prominent thought that was at least in my head was that - at best - Isaac could only ever have been an insufficient sacrifice.
From Genesis 3, throughout the entire Old Testament, we are constantly shown a picture of sacrifice. The picture is shown in the sacrifice of animals. That started when God himself provided animal skins to cover the shame of sin for Adam and Eve (Genesis 3:21). Animal sacrifice was repeated over and over again. There is not one time in the Old Testament that an animal is seen to be sufficient for the once and for all payment of human sin. The author of Hebrews makes that very clear. Hebrews 10:4 For it is impossible for the blood of bulls and goats to take away sins.
God gave the picture of his substitutionary sacrifice in the picture of the shedding of animal blood in the sacrificial system. Animals can never atone for humans. But the sparing of Isaac also shows us that any human that needs a substitutionary sacrifice for his own sin cannot be the substitutionary sacrifice for another. Isaac understood he was walking up a mountain to make sacrifice with his father. He understood this hope of substitutionary atonement for his own sin was pictured in the sacrifice he was expecting to take part in. It seemed, however, he was going to take part in this sacrifice beyond his expectation. He was placed on the altar when God stopped Abraham and spared him. What would it have done if Isaac was sacrificed? Nothing. Not a thing. Isaac could not possibly pay for anyone's sin when he had no ability to even pay for his own.
Can you imagine being the original readers of Genesis as they were about to walk into the land of Cana. The pagan nations occupying that land were known to sacrifice their own children at the altars of their false gods. The biblical account was showing God's people there is no human among us who could atone for our sins and make us right with God - at least not until a sinless human would walk among us.
One of the biggest realities we see in Isaac being spared is that there is only one sufficient human sacrifice for sin. A sinless human. There has only ever been ONE of them.