When God called Abraham out of his hometown and away from all things familiar, He gave Abraham some promises. A covenant is a kind of promise, a contract, a binding agreement between two parties. The fifteenth chapter of Genesis reiterates the covenant God had made with Abraham at his calling. Except this time, God reassures His promise with a visual of His presence. He asks Abraham to find and kill a heifer, a ram, a goat, a dove, and a pigeon. Then, Abraham was to cut them in half (except the birds) and lay the pieces in two rows, leaving a path through the center (Genesis 15:9-10).
In ancient Near Eastern royal land grant treaties, this type of ritual was done to “seal” the promises made. Through this blood covenant, God was confirming primarily three promises He had made to Abraham: the promise of heirs, of land, and of blessings (Genesis 12:2-3). A blood covenant communicated a self-maledictory oath. The parties involved would walk the path between the slaughtered animals so to say, “May this be done to me if I do not keep my oath.” Jeremiah 34:18-19 also speaks about this type of oath-making.
However, there was an important difference in the blood oath that God made with Abraham in Genesis 15. When the evening came, God appeared in the form of a “smoking fire pot and flaming torch that passed between the pieces” (Genesis 15:17). But Abraham had fallen “into a deep sleep, and a thick and dreadful darkness came over him” (verse 12). Thus, God alone passed through the pieces of dead animals, and the covenant was sealed by God alone. Nothing depended on Abraham. Everything depended on God, who promised to be faithful to His covenant. “When God made his promise to Abraham, since there was no one greater for him to swear by, he swore by himself” (Hebrews 6:13-18). Abraham and his descendants could trust, count on, and believe in everything God promised.
This specific blood covenant is also known as the Abrahamic Covenant. The blood involved in this covenant, as with any blood covenant, signifies the life from which the blood comes (Leviticus 17:11).
The Mosaic Covenant was also a blood covenant in that it required blood to be sprinkled on the tabernacle, “the scroll and all the people” (Hebrews 9:19-21). “In fact, the law requires that nearly everything be cleansed with blood, and without the shedding of blood there is no forgiveness” (Hebrews 9:22). In the Mosaic Covenant, the blood of animals served as a covering, or atonement, for the sins of the people. The animal’s life was given in place of the sinner’s life. In the Abrahamic Covenant, God, in essence, was declaring He would give His life if His promises were broken. There could be no greater encouragement to believers, since God is eternal and can no more break an oath than He can die.
All of these things were only “copies,” or “shadows,” of the better covenant to come (Hebrews 9:23). The lives of animals could never remove sin; the life of an animal is not a sufficient substitute for a human life (Hebrews 10:4). The blood of bulls and goats was a temporary appeasement until the final, ultimate blood covenant was made by Jesus the Christ Himself – the God Man (Hebrews 9:24-28). The New Covenant was in His blood (Luke 22:20).
The shadows became realities in Christ, who fulfilled all of the Old Testament blood covenants with His own blood. As the apostle Paul explains, the covenant was established with Abraham and his “Seed”—singular. Paul interprets this as the singular person of Christ (Galatians 3:15-16). Therefore, all who are “in Christ” are spiritual heirs of the promises made to Abraham (Galatians 3:29).
To put it simply, a blood covenant is a promise made by God that He will choose a people for Himself and bless them. The covenant was originally for Abraham’s physical descendants but was later extended, spiritually, to all those who, like Abraham, believe God (Galatians 3:7; cf. Genesis 15:6). God’s promise of eternal blessing is given only on the basis of faith in the saving blood of His Son, Jesus the Christ (Hebrews 9:12).