Abraham expected to walk through the covenant pieces himself. God put him to sleep and walked both sides, sealing a covenant that rests on God alone.
The Shadow
In the ancient world, covenant partners split the sacrificial animals and walked together through the pieces: everything I have is yours, and if I break this covenant, may what happened to these animals happen to me. So when God told Abraham to prepare the animals, Abraham knew what was coming. He was ready to walk his side and bind himself to the Almighty.
And at the most critical moment of his life, God put him to sleep. A deep, supernatural sleep, the same word used when God built Eve from Adam’s side. Then a smoking oven and a burning torch, both representations of God’s presence, passed between the pieces. God stood on both sides of the sacrifice. God walked both directions. The covenant was cut between God and God, with a sleeping man nearby who contributed nothing. Abraham believed the Lord, and it was accounted to him for righteousness, but believing was not his contribution to the covenant. It was his response to watching God do all the work.
The Fulfillment
Hebrews explains why: when God made the promise, He could swear by no one greater, so He swore by Himself. The promise was to Abraham, but the oath was to God, anchored to a character that cannot lie and cannot change. That is why hope is an anchor of the soul, sure and steadfast, fastened behind the veil to Jesus Himself, not to your consistency.
Fast forward to a hill outside Jerusalem: two crosses on either side, a path between them, and God in the middle, walking through. Where were you while the covenant was sealed? Where Abraham was. Asleep. While we were still sinners, Christ died for us. God did not need your walk; He needed you out of the way, so the thing He was doing could never be undone by the thing you might do.
Him All Along
If you carry the quiet fear that your failure might collapse the whole arrangement, you are picturing a bilateral covenant. Genesis 15 says otherwise. God walked your side. If we are faithless, He remains faithful. The covenant is sealed, and the One who sealed it did not need your legs to finish it.