We have been looking at God's plan of redemption that lies behind Jesus' statement that He had to suffer, die, and rise from the dead (Mark 8:31). Our Lord's sense of obligation was born from the covenant He made with the Father and the Holy Spirit to save the elect from the sin and guilt Adam brought on humanity when he broke the covenant of works. This salvation would involve Christ's coming as the last Adam who would obey God where we did not and crush Satan (Gen. 3; Rom. 5:12–21). It would take place in an arena made stable by God's covenantal promise to Noah not to destroy the earth with a flood again (Gen. 8:20–22).
Thus, the plan of salvation would be unfolded in a series of covenants in which two parties pledged to fulfill obligations to one another. These covenants include blessings for those who meet their obligations and curses for those who do not, such as the covenant of works' blessing of eternal life and curse of death (Rom. 5:12–21).
The glory of the gospel is that God assumed the covenant curses Himself in the person of Christ to save us and thereby reveal His love and justice (Rom. 3:21–26; Gal. 3:10–14). Today's passage anticipates our Creator's willingness to take on the covenant curse. In the ancient Near East, covenants were actually "cut," as the term used for making covenants is the Hebrew word that means "to cut." That terminology likely derives from the ceremony wherein a covenant was ratified. During the covenant ratification ceremony, the parts of several killed and dismembered animals were laid side by side with a path between them. The parties to the covenant would walk between the animal pieces while swearing oaths to keep the covenant. In effect, they were calling for the curse that fell on the animals—death—to fall on them if they should break their covenant vows.
Genesis 15 describes how God used such a ceremony to assure Abraham that He would give the patriarch an heir who would bless the world. But note that the only party to the Abrahamic covenant who passed between the animals was the Lord, who manifested Himself as a pot and torch. God was calling for His own death should the covenant not be fulfilled, but since He cannot die, that meant His promises would certainly come to pass. To ensure that the covenant would not fail, God essentially adopted all the aspects of the covenant Himself, even the curse that Abraham would have submitted to had he passed between the animal pieces as well.
Abraham's descendants—the people of Israel—failed to uphold their covenant obligations. All they deserved was death and the consequences of failing the covenant. However, God showed Himself willing to take on the curse Abraham's descendants deserved, thereby upholding divine justice even while fulfilling the covenant Himself. That is the great love of God—He does not let our sin and failures stop Him from blessing His chosen.