Genesis 12 " Now the LORD had said unto Abram, Get thee out of thy country, and from thy kindred, and from thy father's house, unto a land that I will shew thee:2And I will make of thee a great nation, and I will bless thee, and make thy name great; and thou shalt be a blessing:3And I will bless them that bless thee, and curse him that curseth thee: and in thee shall all families of the earth be blessed."
4So Abram departed, as the LORD had spoken unto him; "
abram then rescues Lot in the battle of the kings, and meets melchezidek who brings him bread and wine, and blesses Him along with God Most High. again this is before the law was given through the levitical priesthood order.
Genesis 14 " And Melchizedek king of Salem brought forth bread and wine: and he was the priest of the most high God. ( see hebrews 4-9) 19And he blessed him, and said, Blessed be Abram of the most high God, possessor of heaven and earth:20And blessed be the most high God, which hath delivered thine enemies into thy hand. And he gave him tithes of all."
Genesis 15 " And, behold, the word of the LORD came unto him, saying, This shall not be thine heir; but he that shall come forth out of thine own bowels shall be thine heir. 5And he brought him forth abroad, and said, Look now toward heaven, and tell the stars, if thou be able to number them: and he said unto him, So shall thy seed be. 6And he believed in the LORD; and he counted it to him for righteousness.
after Isaac is born, God then puts abrahams faith to the test.
Genesis 22 " And it came to pass after these things, that God did test Abraham, and said unto him, Abraham: and he said, Behold, here I am. 2And he said, Take now thy son, thine only son Isaac, whom thou lovest, and get thee into the land of Moriah; and offer him there for a burnt offering upon one of the mountains which I will tell thee of......
v5 Then on the third day Abraham lifted up his eyes, and saw the place afar off. .....v6And Abraham took the wood of the burnt offering, and laid it upon Isaac his son; and he took the fire in his hand, and a knife; and they went both of them together. 7And Isaac spake unto Abraham his father, and said, My father: and he said, Here am I, my son. And he said, Behold the fire and the wood: but where is the lamb for a burnt offering? 8And Abraham said, My son, God will provide himself a lamb for a burnt offering: so they went both of them together.
9And they came to the place which God had told him of; and Abraham built an altar there, and laid the wood in order, and bound Isaac his son, and laid him on the altar upon the wood. 10And Abraham stretched forth his hand, and took the knife to slay his son.
11And the angel of the LORD called unto him out of heaven, and said, Abraham, Abraham: and he said, Here am I. 12And he said, Lay not thine hand upon the lad, neither do thou any thing unto him: for now I know that thou fearest God, seeing thou hast not withheld thy son, thine only son from me.
...v 15And the angel of the LORD called unto Abraham out of heaven the second time, 16And said, By myself have I sworn, saith the LORD, for because thou hast done this thing, and hast not withheld thy son, thine only son: 17That in blessing I will bless thee, and in multiplying I will multiply thy seed as the stars of the heaven, and as the sand which is upon the sea shore; and thy seed shall possess the gate of his enemies; 18And in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice. "
paul says the gospel was preached to abraham in advance here and that it is a promise for the gentiles to be blessed through abrams seed. That God is promising to " provide a lamb for himself for an offering" to give" His only begotten son" that all nations of the earth would be blessed in abrahams seed, and that seed paul says is Christ. Notice this is not of the dovenant God made later with israel, but it was before. the law then excludes all people on earth. then Jesus comes and sends His gospel out to all people of earth saying " God has forgiven us, come home repent and return to God"
so abraham was hearing about Jesus here in this story. and of course the nature and details of the story......" the Father sacrificing His only begotten Son, carrying the wood upon his back up the mount, being laid upon the altar and bound upon the wood" ...it sort of makes sense what paul is saying here regarding the gospel preached to abraham.
Galatians 3 " Even as Abraham believed God, and it was accounted to him for righteousness. ( <<<not of the law) 7Know ye therefore that they which are of faith, the same are the children of Abraham. ( not abram, but abraham) 8And the scripture, foreseeing that God would justify the heathen through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed. 9So then they which be of faith are blessed with faithful Abraham."
Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ. 17And this I say, that the covenant, that was confirmed before of God in Christ ( in abraham) , the law, ( of moses) which was four hundred and thirty years after, cannot disannul, <<<that it should make the promise of none effect. 18For if the inheritance be of the law, it is no more of promise: but God gave it to Abraham by promise.
all this said, if abraham had not obeyed God he would never have been the man of faith. he was blessed because he believed God enough to actually do what God said to do, because he believed if he did it as God said, the promise would come as God said. the promise isnt " i will bless you abram" it is " get thee up and get out of your homeleand and go where i show you and i will bless you and all people ofthe earth...."
Thats what we have to do in Christ, we have to believe what Jesus said to do, and how to believe and do it because we Believe his promise about receiving eternal Life in His Kingdom that is in Heaven. Faith does not mean we need not believe what Jesus Christ said, its the reason we should believe Him. because He is the One God sent to tell us these things about the resurrection and eternal Life. Faith believes Gods instructions, and His promises.
God bless. think of paul in ot context hes explaining things from scripture.