The story of God calling Abraham to sacrifice his long-awaited son, Isaac, is one of the toughest accounts in the whole Bible for me to grapple with. Why would a good God ask his faithful follower to do something that seems so contrary to his nature…so downright cruel? Yes, there’s a graceful finish to the story, but Abraham didn’t know that when he and his beloved son started their hike up the mountain.

Recently, though, I read something in Tim Keller’s book Counterfeit Gods that shed new light onto this story. According to Keller, in the cultural and religious backdrop of Abraham’s day, it was a given that every firstborn son belonged to God. Although these sons were to be bought back through sacrifice (Exodus 22:29; 34:20), they were still viewed as belonging to God—something of a down payment for the family’s sins. So in reality, Keller contends, God wasn’t asking Abraham to commit murder; he was asking him to lay down what was rightfully his.

Still, Abraham was left in a quandary. He believed God was holy, so he must hand over his son. Yet he also believed God was gracious and would keep his promises. How could both be true?

As I think about Abraham and Isaac making their way up the mountain on their sacrificial journey, I marvel at Abraham’s obedience. How was he able to put one foot in front of the other knowing what awaited him at the top? Keller captures Abraham’s faithfulness this way: “If he had not believed that he was in debt to a holy God, he would have been too angry to go. But if he had not also believed that God was a God of grace, he would have been too crushed and hopeless to go” (p. 11).

Keller goes on to point out that the biblical account offers a beautiful foreshadowing of grace: “He told his servants that ‘we will come back to you’ (Genesis 22:5). It is unlikely he had any specific idea of what God would do.” But he clung to the hope that God would somehow stay true to his character.

And he did just that. He provided a substitute—a ram in place of Abraham’s son.

This is, in the end, a beautiful account of eleventh-hour grace. Even so, it pales next to the ultimate story of sacrifice and grace: God’s own Son, laid on the altar by his Father. The substitute for our sin. Once and for all.

I’ve taken the challenge of reading the Bible chronologically this year and tracing the thread of grace through it. These musings are prompted by my reading. I’d love to have you join me: One Year Bible reading plan.