Abram (Abraham) believed God.

Abram believed Yahweh God and Abram's faith in the WORD of God was credited to him as righteousness. ^{(Genesis 15 verse 6.)} 

Before Elohim God created the world, His Covenant was with His own WORD, for His WORD was His Perfect Lamb that would come into the world be born as the Son of  Man, and would be slain for the sins of Man.  In the Garden of Eden, the Almighty God would bring forth from the side of Adam the pure genetics from Adam's rib to be for Elohim's creation of Woman, known in Hebrew as Ishshah.  Elohim God gave one warning instruction to Adam; Of  every trees in the Garden you may freely eat, but of the Tree of Knowledge of Good and Evil you must not eat of it, for in the day that you eat of it, you will definitely die.  All was well in the Garden until Satan, originally known as Lucifer, formed himself into a serpent and made himself to be one with the Tree of Knowledge of Good and Evil.  Both Adam and Ishshah were present at the Tree of Knowledge and were beguiled by the wisdom of the serpent that had affixed itself to the Tree of Knowledge of Good and Evil,  In their unholy self righteous conviction, they aligned themselves with the deception of the beguiling serpent, and broke faith with their Creator, for they both ate of the fruit from the Tree of Death.  In their nakedness they became ashamed and attempted to hide themselves from their Maker.

Finding the pair in their naked shame, Elohim God then declared judgment upon Satan and his corrupting evil forces. I will put enmity between you and Woman/Ishshah ^{(Ishshah is the name of Adam's wife in the Garden)}, and between your seed and her seed; He [the Seed of Ishshah] will crush your head, and you will strike His heel. ^{(Genesis 3 verse 15.)}

Holy Yahweh God of Eternal Righteousness, would maintain throughout time His Covenant Word given before the Foundation of the world, for His very own Lamb would come into the world and be born the Son of Adam. With the reception of the Word of God delivered by Gabriel, the virgin Mary would conceive the LIFE of Christ by Yahweh God's Spirit of Holiness, and after the gestation period, Mary gave birth to the genetic Son of the first Adam, who would be the Last genetic Adam.

Sin has its own punishment of death, and now the sinless Lamb of God would be made to be sin for mankind, and at the hand of the man of sin, the sinless Lamb of God would be crucified to death for the sin Man,   The death of the innocent genetic Son of the Man Adam was the full  payment for the sin of  the first Man,  Death for death.  Jesus Christ, the Man would indeed crush the head of insurrection, but in the Messiah's Holy innocency, Yahweh God would raise Yeshua from the dead.  Paul writes of the hidden wisdom of Yahweh God that was ordained before the foundation of the world, of which none of the  princes of this world knew: for had they known of the hidden wisdom of God, they never would have crucified the Lord of Glory.

Elohim God's Promised Messiah, with His Perfect Love and Obedience to His Father Yahweh God,  would end the conflict of sin and death in man once and for all time, for all those who have the obedient faith of Abraham.  The Grace of Yahweh God, through the victory of Jesus Christ, would save humanity through Yahweh's Gift of His Spirit of LIFE that restores faith IN the Almighty's WORD of TRUTH.  The Love of His Father Yahweh God was with-IN Jesus Christ, and as the true genetic Son of the first Man/Adam, Jesus the son of Man would overcome and defeat the evil one of sin and death, with his death and resurrection.  All, who would repent and believe in Yahweh God's Salvation WORD, would be saved through their testimony of faith in the crucified sinless Seed of a virgin woman.  The incarnate Son of God, made to be sin, was the Seed of Woman crucified to death for the sins of the world, and because Jesus bore no sin, He was raised to LIFE because of Yahweh God's Righteous Judgment.

Jesus the Man, was sacrificially crucified to death for all of the guilty of mankind, so that, whosoever should believe in Jesus/Yeshua's death and His resurrection into LIFE should not perish, but have everlasting LIFE IN Christ.  God's Holy Son is the TRUTH and the WAY and the only LIFE that restores mankind to His Father Yahweh God.  Sin and death could not hold in the grave, the Perfect Love of the Son of Man, for the Son loved His Father IN perfect Obedience. 

Yahweh God would preserve His Promised Seed of Ishshah/Woman taken from the genetic flesh of Adam.  In the Infinite  Creator's foreknowledge of all time, Yahweh God would save the generationally pure Noah, and his immediate family from the flood that Yahweh God would bring upon the wicked.  God brought forth the destroying flood in judgment for the destruction of the wickedness of all flesh, that had been genetically and spiritually corrupted through the fallen angelic sons of God. ^{(See Genesis 6.)}

Here are the generations of Noah, beginning with his son Shem, his son Arphaxad,  his son Shelah, his son Eber, his son Peleg, his son Reu, his son Serug, his son Nahor, his son Terah, and his son Abram; the same is Abraham.

And God told Abram to leave his country and his father's house, and journey into the land of Canaan that God would give to Abram and his genetic seed.  Abram began to believe and trust in the one God.  Now we see in Scriptures that because Abram obediently departed his homeland at God's behest, Yahweh God would reveal to Abram the extent of His Covenant Promise that He gave in the Garden of Eden, and that He the Creator would extend that Covenant Promise to Abraham and his genetic seed.  God would protect His Word and the Covenant of the Seed of Ishshah/Woman, to bring forth His Great Salvation to save mankind from the violence of sin and death, and destroy in His flesh of Man, those corrupting works of Satan.

After these things, the Word of the Lord came unto Abram in a vision. --- Then in the midst of vision, the Lord God said unto Abram: I AM the Lord that brought thee out of Ur of the Chaldees, to give thee this land to inherit it.  Abram said, Lord God, whereby shall I know that I shall inherit it?  And the Lord God said unto him: Take Me an heifer of three years old, and a she goat of three years old, and a ram of three years old, and a turtledove, and a young pigeon.  And Abram took unto the Lord all these, and divided them in the midst, and laid each piece one against another: but the birds divided he not.  And when the sun was going down, a deep sleep fell upon Abram; and, lo, an horror of great darkness fell upon him. And it came to pass, that, when the sun went down, and it was dark, behold a smoking furnace, and a burning lamp that passed between those pieces. ^{(See Genesis 15 verse 1 thru 21.)}

The Good News that is the Gospel, is based on mans' return to God, through a heart of faith that believes IN the sacrificial obedient love and faith of God's Only Begotten and beloved Son Jesus Christ.  For indeed, the Word of God is the Person of absolute TRUTH, and to be TRUTH of God, the Word of God must be genetically pure as the Son of Adam/Man, born of the Seed of Woman.  That justifying faith is witnessed by the Word of God with Abraham's faith in the Covenant Promise of God.  Jesus speaking to the Pharisees says: Your father Abraham rejoiced to see My day: and he saw it, and was glad. ^{(John 8 verse 56.)} No doubt you will ask, even as I have pursued this question: When did Abraham see the day of the Lord?  We postulate in the excellencies of hindsight and with a little experience that that day happened when, as Paul says, the Gospel was first preached to Abram, In the same day  the Lord made a covenant with Abram, saying unto thy seed have I given this land.  Abram became a man enlarged in faith, trusting in God's Promised Word of Redemption from sin and death. ^{(See Galatians 3 verse 8 thru 9.) (Likewise 2nd Chronicles 20 verse 7.)}

In a vision, Yahweh God put Abram into a deep sleep, and Abram, in the initial horror of that visionary dream state, witnesses the Lord Himself, present Himself, as His Covenant Security of the Promise that He had made to Abram.  Abram's genetic lineage from his Shemetic fathers, would continue in generational time, to a virgin woman of like faith, and her ovum would be impregnated with the Covenant Word of Father Yahweh God Almighty.  That Incarnate Seed of Yahweh's Messiah, would crush the head and will of Satan, thereby fulfilling not only Yahweh God's Word given after the garden fall of Adam, but also God's essential Covenant Promises made to Abram and his offspring that followed in Abraham's faith in God's Redemptive Promise. 

So then, in the horror of the darkness of his sleep, Abram saw the Son of God, as the One speaking to him, confirming the Almighty's Covenant Word IN His Sacrificial Life Blood.  The Almighty would protect His Holy Word, and at the appropriate time, the generational Son of Adam/Man from the lineage of Abram's generational seed, was crucified to death. So then, in all probability, Abram witnessed in a vision, his Lord as a lifeless corpse in the grave, only to rejoice in the gospel's good news, of the glorious bodily resurrection of His Lord, the then pre-incarnate Christ of God.  The Covenant of Promise is confirmed in Abram's heart when the Smoking Furnace and the Burning Lamp together passed between the sacrificed animal pieces.  For the sake of lost mankind, the Covenant of Promise of God is sealed between Father God Almighty (the Smoking Furnace) and the WORD of God (the Burning Lamp), Who would represent the Son of Adam as the seed of Abram.  Now to Abram and his seed were the Promises made.  The Lord said not, and to seeds as many; but as of One:  And to thy Seed, Which is Christ, Who was from the beginning was God's Promised seed from Ishshah/Woman. ^{(See Galatians 3 verse 16 thru 18.)} By the Seed and Word of Christ Jesus alone are we made to be a new genesis of man, created in the image and likeness of God's only begotten Son.

Note: Some theologians have speculated that the smoking furnace, and the burning lamp preformed the figure of infinity ∞ when they passed between the dead carcasses, and that also an oath was sworn at that time by the burning lamp, concerning the promises God made to Abram.  It may have been something to this effect: Let me be as these carcasses, if I do not fulfill the promises of this covenant of My Word to Abram. ^{(See Zechariah's prophecy to Mary in Luke 1 verse 72 thru 73, and then Genesis 12 verse 3.)} For when God made promise to Abram, and because He could swear by no greater that Himself, He swore upon Himself.  In the Prophecy of Scripture, we witness the TRUTH testifying that His Covenant with Abram was based on His Word alone, but His Word would be confirmed with the Blood of God's Lamb, slain even before the foundation of the world.

Then said I, in the volume of the book it is written of Me, to do thy will, O God.  In the Garden the Lord God said to Satan: I will put enmity between thee and the woman, and between thy seed and her Seed: her Seed shall bruise thy head, and you shall bruise His heel. ^{(See Hebrews 10 verse 4 thru 10, Psalm 40 verse 4 thru 10,Genesis 3 verse 15, and Isaiah 7 verse 14.)} Abram, who would become the father of faith, saw the day of Jesus Christ, and rejoiced in His Lord and Savior for the Messiah of God was to come, even through Abram's own genetic seed, for the Word of God Almighty was already fulfilled in God's creation of time.  And in the great Mystery of God, none of the rulers of this world had known: for had they known of the Mastery, they would not have crucified the Lord of glory. ^{(See 1st Corinthians 2 verse 7 thru 10.)} The enemy of sin and death was vanquished in the resurrection of the pure genetic Son of Man, for Jesus/Yeshua was the pure Eternal Son and the TRUTH of the Word of Father God.

The name  Abram, God changes to Abraham

And some years later, when Abram was 99 years of age then the Lord again appeared to Abram and Said: I AM the Almighty God, walk with Me, and you will be perfect.  I Will make My Covenant between Me and you and will multiply you exceedingly.  As concerning Me, understand My Covenant with you, for you shall be a father of many nations. Therefore, thy name shall no longer be called Abram, but your name shall be called Abraham; for I have made you a father of many nations. ^{(Genesis 17 verse  1 thru 5.)}

My Covenant  I will establish with Isaac, which Sarah shall bear unto you at the set time, in the next year. In the very same day was Abraham circumcised and also Ishmael his son.  All the men of the his house, born in the house of Abraham, even though they may have been strangers bought with money, they were circumcised as a sign that they were enjoined in the Covenant of Yahweh God Almighty.