The Lord God sovereignly dictates the terms of His covenant with His people. 
Particular example = Abraham. (No agreements, negotiations, or debates)
A covenant is not a contract where both parties agree to certain stipulations.
LOOK @ GEN 15
Abraham didn't need any special instruction. He knew the procedure well. It was the custom
of his day. He divides the beasts but not the birds.
vs16- "The grace of God's longsuffering toward the current inhabitants of the land explains
the delay."
Participants who passed between the pieces were asking that their bodies be torn in pieces
just like the animals if they should fail in the covenant.
LOOK @ JER 34
Jerusalem under siege by Babylon  vs 1,6-7
Zedekiah assembled the people for a covenant renewal ceremony  vs 8-9
Zedekiah mentions the sabbatical release of Israelite slaves  vs 10
LOOK @ JER 34:17-20
Jeremiah knew that his description of covenant renewal would be understood by his hearers.
This is no literary allusion to Gen 15; this is a real covenant renewal ceremony.
LOOK AGAIN @ vs 18-19
This was something the people in Jeremiah's day did, and it corresponded to something done
in Abraham's day.
But more important now is the correspondence to the covenant ceremony made by Moses. Zedekiah
assembled the people and read the law. This was established by Moses not Abraham.
LOOK @ Ex 24:1-8
The reading of the law would have brought up the need for the sabbatical release of the
Hebrew slaves. "They had been redeemed from bondage; they were never to return to bondage."
This was written in Exodus (21:1-3), Leviticus (25:39-43) and Deuteronomy (15:1, 12-18).
But unlike the ceremony recorded by Moses, Jeremiah records that the people passed between
the pieces.
In the ceremony for Moses then, there was something that involved the same commitment without
having millions of Jews pass between the pieces.
It would appear that the blood sprinkling of Ex 24:8 was the substitute for passing between
the pieces.
The blood not only symbolized cleansing the people, but it also "consecrated them to keep the
covenant on pain of death."
LOOK AGAIN @ JER 34:20
Cf GEN 15:11
Abraham drove away the birds of prey. That's the ultimate fate of the covenant breaker: being
driven away, having his body slain and torn and devoured by wild birds of the heavens.
Dt 28:26
    Your carcasses shall be food to all birds of the sky and to the beasts of the earth,
    and there shall be no one to frighten them away.
I Kings 14:11
    Anyone belonging to Jeroboam who dies in the city the dogs will eat. And he who dies
    in the field the birds of the heavens will eat; for the Lord has spoken it.
I Kings 16:4
    Anyone of Baasha who dies in the city the dogs shall eat, and anyone of his who dies
    in the field the birds of the heavens will eat.
I Kings 21:24
    The one belonging to Ahab, who dies in the city, the dogs shall eat, and the one who
    dies in the field the birds of heaven shall eat.
II Kings 9:10 (Jezebel)
    And the dogs shall eat Jezebel in the territory of Jezreel, and none shall bury her.
Jer 7:33
          And the dead bodies of this people will be food for the birds of the sky, and for the
    beasts of the earth; and no one will frighten them away.
Jer 16:4
    ...and their carcasses will become food for the birds of the sky and for the beasts of
    the earth.
Jer 19:7
    ...and I shall give over their carcasses as food for the birds of the sky and the
    beasts of the earth.
All of this reflects "the covenantal form employed by God in binding Himself to Abraham."
All of this also shows that throughout Israel's history the covenantal pledge to death was
never forgotten or lost.
"...the New Testament interprets the new covenant in terms of relief from these same curses."
LOOK @ HEB 9:15-20
diatheke = in Grk either "last will and testament" or "covenant"
"The death of a testator activiates the provisions of his will." This is easily understood
for us today.
But the relation of death and covenant is not so obvious. We don't see covenants after a
Biblical pattern in modern culture.
But we have just seen in Scripture, that "essential to the inauguaration both of the
Abrahamic and Mosaic covenants was the symbolic representation of the covenant-maker."
"Death of the covenant-maker receives symbolic representation at the time of the inauguration
of the covenant."
"Death of the covenant-violator receives historical actualization when covenantal judgment
is executed."
"So both 'testament' and 'covenant' involve death."
    "Death activates a testament."
    "Death inaugurates and vindicates a covenant."
LOOK BACK @ HEB 9:15
"The diatheke in Heb 9:15 is the Mosaic covenant." God didn't establish a last will and
testament with Moses; God established a covenant through Moses.
The death of a testator doesn't remove transgressions against a last will and testament.
But Christ's death removes transgressions under the first covenant. It was Christ's blood of
the covenant that was shed.
Christ didn't die to activate a will for Israel.
LOOK @ vs 17
A testament is not made firm over dead bodies or dead men. "Only one body is required for the
activation of a last will and testament. But a multiple of dead bodies is associated
immediately with the inauguration of a covenantal relationship. Many beasts are slain to
symbolize the potential of covenantal curse."
LOOK @ vs 18
This is blood shedding that is associated with covenant inauguration.
Christ's death is to be understood in terms of God's dealing with His people throughout
history.
Christ bore the covenantal consequences of the original pledge-to-death by God.
This is what it means to say that Christ delivers from the curse of the covenant.
LOOK @ Matt 26:28
Christ uses covenantal language. He is the substitute, the sacrifice, the one upon whom the
curses of the covenant were placed.
LOOK @ Lk 22:20
"Not only does Christ's blood remove the curse of the old covenant; simultaneously it
introduces the blessed condition of the new covenant."
CONCLUSION:
God's covenant with Abraham is one of promise. God promised redemption.
God promised by passing between the pieces Himself, instead of Abraham.
God promised to see that every promise of the covenant was realized.
Think about the promise, think about how secure it is. The promise cannot fail because God
cannot fail. And even more sure is the fact that God cannot absolutely destroy Himself; He
is eternal. He will make sure the covenant is kept. He provided Christ as the ultimate pledge
to death. Christ had His flesh torn and His blood shed for our covenant transgressions.