Why "cut" and not "make"
The Hebrew Bible never says "make a covenant." It says karath berith — cut a covenant. The same verb is used for chopping wood (Deut 19:5), severing a head (1 Sam 17:51), and slaughtering an animal (1 Kings 19:21). A covenant is a cutting, and the cutting is the substance of the act, not a metaphor.
The Akkadian cognate kāratu shares the root and the meaning: the standard ANE practice was to slaughter animals, divide them in halves, and lay the halves opposite each other forming a path. The covenant parties then walked between the pieces. The act invoked the death-curse of the animals on themselves: if I break this covenant, may I be made like these halved animals.
This is documented across the ANE: the Mari texts (18th c. BC), the Sefire treaty (8th c. BC, Aramaic), the Hittite suzerainty treaties (14th c. BC). The covenant-cutting practice is international. Genesis 15 places Abram inside a recognizable cultural frame.
Genesis 15 — what is unprecedented
Where Genesis 15 breaks with the ANE pattern is who walks the path.
Abram cuts the heifer, the goat, the ram (each in halves), and lays the dove and the pigeon whole (per ANE bird-rite norms). He drives away the birds of prey. Then:
"And when the sun was going down, a deep sleep fell upon Abram; and, lo, an horror of great darkness fell upon him." (Gen 15:12)
Abram does not walk. He sleeps. Only God — manifest as a smoking furnace and a burning lamp (compare the pillar of cloud and fire at Sinai) — passes between the pieces.
The death-curse is invoked only on God. This is unprecedented in the ANE record. Every other covenant-cutting ceremony has both parties walk and both invoke the curse. Here, God walks alone and bears the entire weight of the covenant''s sanctions.
What this means at Calvary
The theological consequence is the cross. Hebrews 9:15–17 names it directly:
"And for this cause he is the mediator of the new testament... For where a testament is, there must also of necessity be the death of the testator. For a testament is of force after men are dead: otherwise it is of no strength at all while the testator liveth."
The Greek diathēkē covers both "covenant" and "testament" (a will requires a death). The death-curse Abram should have walked under, God walked under at Calvary. The smoking furnace and the burning lamp at Genesis 15 — God''s self-binding to the covenant — find their consummation in the wood at Golgotha.
This is also why Galatians 3 can argue the law (Mosaic, conditional) cannot annul the Abrahamic (unilateral, unconditional). The Abrahamic was cut by God alone walking the path. No one else can break it because no one else is bound by it. The death-curse falls on God or on no one.
The Last Supper — a cup, not a path
When Jesus institutes the new covenant in Luke 22:20 — "This cup is the new testament in my blood" — he uses diathēkē. The path between the pieces in Genesis 15 has become the cup at the table; the smoking furnace has become the body broken; the burning lamp has become the wine poured. The covenant is still cut, but now it is cut on God''s own body.
The pattern, from Abram''s sleep to the cross, is exact: God alone walks; God alone bears; God alone cuts.