In watching Jesus carry the wood of the cross to the place of execution, Christians naturally think of the story of Abraham and Isaac in Genesis 22. God said to the patriarch, “Take your son, your only son, Isaac, whom you love, and go to the region of Moriah. Sacrifice him there as a burnt offering on one of the mountains I will tell you about.” Abraham obeyed God, and Isaac quietly carried the wood up the mountain, preparing to be slaughtered by his own father.

In many ways, the story is disturbing, repugnant, and infuriating. We want to know what it was that drove Abraham up the mountain to take the life of his beloved son. We want to know why Isaac was so passive and compliant in the whole affair. And we want to know why God intervened at the last possible moment, possibly traumatizing Isaac even further. The entire episode is a bit more comprehensible when we understand that covenants often involved the exchange of firstborn sons. But sending Isaac to live in God’s house would necessitate his death. That’s hard to take.

Yet it was precisely because Isaac’s life was on the line that something even more horrendous than child sacrifice was at issue—namely, the possibility that God could be a liar. After all, Isaac was the child of promise, so if he died, God’s trustworthiness would die with him. Isaac has to live—or be resurrected—if all nations of the earth are to be blessed through his line. Abraham knew this, as the New Testament tells us in Hebrews 11:17. Abraham was convinced that God cannot lie, so he raised the knife. Just then an angel of the Lord called out from heaven, “Abraham! Abraham! Do not lay a hand on the boy. Do not do anything to him. Now I know that you revere God, because you have not withheld from me your son, your only son.” Abraham looked up, and there in a thicket was a ram caught by its horns. He took the ram and sacrificed it as a burnt offering in the place of his son. Amazing.

Genesis 22 is a story about the costly sacrifice of a father, the willing submission of a son, and the gracious provision of the Lord. “He will provide,” said Abraham. “The Lord will see to it.” No wonder Jesus said to his contemporaries, “Your father Abraham rejoiced at the thought of seeing my day; he saw it and was glad” (John 8:56). Jesus was now part of a similar story himself, and Abraham had gotten a preview of it. But what did Abraham see when he was standing on Mount Moriah? What did he hear? What did God show him? Did Abraham see the obedient Son of God bearing the wood of the cross to Golgotha—the Son for whom there would be no substitute this time? Perhaps if Abraham had been standing at the foot of the cross and had seen Jesus die right in front of him, he would have looked up to heaven and spoken God’s words back to him: “Lord! Lord! Now I know that you revere me, for you have not withheld from me your Son, your only Son, Jesus, whom you love.”

This message shows how the hardest thing God could ever ask of us is the very thing he did for us—he gave us his only Son.That Son was a descendant of Abraham through Isaac, and all families of the earth are blessed through him. God kept his word. Again. “What, then, shall we say in response to this? If God is for us, who can be against us? He who did not spare his own Son, but gave him up for us all—how will he not also, along with him, graciously give us all things?” (Romans 8:31-32). Even more amazing.