The Old Testament is all about grace. It contains some laws and talks about judgment. But at the end of the day, the whole thing is held together by grace. If you pull grace out, like tugging on a loose thread from a sweater, the whole garment will become undone. Grace is the backbone of the Old Testament story.

And it begins in Genesis 15, when God confirms his covenant (his agreement) with Abraham. Back in Genesis 12, God promised to bless Abraham, give him tons of kids, and use him to bring salvation to the nations (12:1-3). But God’s promise still needs to be visibly confirmed, and that’s what Genesis 15 is all about. God wants to show Abraham that he is serious about what he has committed himself to. And so God and Abraham perform an ancient ritual that was common in their time.

“God said to him, ‘Bring me a heifer three years old, a female goat three years old, a ram three years old, a turtledove, and a young pigeon.” And he brought him all these, cut them in half, and laid each half over against the other.” (Gen 15:9-10)

Now, this seems like a really bizarre event, but it’s only bizarre to us. Back in Abe’s time, this was a typical ceremony that two people would carry out in order to confirm an agreement they were making. Say, for instance, an ancient dude named Wayne wanted to sell his camel to another dude named Winston. In exchange for the camel, Winston agrees to let Wayne marry his daughter. Now, Winston may walk away with the camel right then, but his daughter’s only 11 years old. She’s not going to be given over to marriage for another two years! (Yes, they got married at 13.) So Wayne’s a bit worried that Winston may go back on his promise, and so in order to confirm the promise that they made, both Wayne and Winston would take an animal, kill it, and cut its body in half. Then, they would divide the two parts by a few feet and both Wayne and Winston would walk between the two bloody parts of the animal. (I apologize to my UK readers for the profanity.) And by walking between the two parts, both members visibly confirm that they will not go back on their word. Wayne demonstrates that he will give up his camel. Winston demonstrates that he will give up his daughter.

When they walk between the two parts of the animal, this was a visual and quite vivid proclamation: “May I be like this dead animal if I go back on my word.” That’s the purpose of the dead animal. To remind the two people that this is what will happen if they go back on their word.

And this is the point of the story in Genesis 15. God has already promised to be with Abraham, to make him into a nation, to bless him and keep him. They now only need to ratify their agreement. So Abraham kills some animals and divides their dead bodies, so that he and God can walk between the two parts. In doing so, God would show they he will keep his half of the bargain, and Abraham would keep his half of the bargain. And if either one fails to keep his word, then let them be like these dead animals.

The thought of God taking upon himself such an oath—a promise to keep his word or die—is unthinkable and borders on heresy. Can God take upon himself such an oath, that he would become like these two dead animals if he fails to keep his word?

Not only is the answer Yes, but there’s more to it. The ceremony is a radical depiction of Grace, one which breaks all the rules and breaks down the conventions of transaction and merit. Because when it comes time to walk between the two animals, God causes Abraham to fall into a deep sleep, while God—and God alone—passes between the bloody corpses.

“As the sun was going down, a deep sleep fell on Abram. And behold, dreadful and great darkness fell upon him…When the sun had gone down and it was dark, behold, a smoking fire pot and a flaming torch [= the presence of God] passed between these pieces.” (Gen 15:12-17)

God takes upon himself the SOLE responsibility to carry out his promise. May I be like these dead animals if I fail to keep my word to be your God, to bless you and to save you, to be with you until the end.

This is not the way it was supposed to happen! No one in the ancient world would make such a ridiculous covenant—to agree to do something for another person without the confirmation that they will do something for you. This is too risky, too one-sided, too unconditional!

Welcome to the Old Testament, where grace tethers the whole thing together. Like a beam of light refracted through a priceless gem, grace penetrates the Abrahamic covenant and sparkles every story from Genesis to Malachi.

I see a very common problem in the Christian church that thinks that God first saves us by his grace, but then it’s up to us to maintain God’s love by what we do. Most people don’t say this, but many live like it. I see it all the time. We begin the Christian journey so thankful for God’s grace, but as we grow in Christ we begin to leave behind grace and bank on our own efforts to sustain God’s love for us. And so if we have a bad day, or a bad week, or we go a couple months being apathetic or disengaged, we think that God loves us less. When we perform well, we think God loves us more.

But when God saved you, he did so based on who he is and what Christ has done, not because of what you did or didn’t do. Like Abraham, you overslept the covenant ceremony when God fashioned your salvation through Calvary and the empty tomb. Though you found out about it recently, God saved you 2,000 years ago and no struggle with apathy will reverse God’s cosmic work on your behalf. It was God, not Abraham—and certainly not you and I—who walked between the dead animals shouldering the responsibility to maintain his vibrant divine love toward you.