Abraham, being the father of the faithful believed God and rejoiced to prophetically be given knowledge of (see) the prophesy fulfilled through his biological seed Isaac from whom the promised (Seed) Messiah, Savior would be born. The desire of Abraham was NOT for the physical promised land of Old, where he saw himself as stranger and pilgrim on the earth. His heart's desire was a far better country, that is an heavenly country prepared for them a city, Heavenly Jerusalem not of this world but from above.
Hebrews 11:11-19 (KJV) Through faith also Sara herself received strength to conceive seed, and was delivered of a child when she was past age, because she judged him faithful who had promised. Therefore sprang there even of one, and him as good as dead, so many as the stars of the sky in multitude, and as the sand which is by the sea shore innumerable. These all died in faith, not having received the promises, but having seen them afar off, and were persuaded of them, and embraced them, and confessed that they were strangers and pilgrims on the earth. For they that say such things declare plainly that they seek a country. And truly, if they had been mindful of that country from whence they came out, they might have had opportunity to have returned. But now they desire a better country, that is, an heavenly: wherefore God is not ashamed to be called their God: for he hath prepared for them a city. By faith Abraham, when he was tried, offered up Isaac: and he that had received the promises offered up his only begotten son, Of whom it was said, That in Isaac shall thy seed be called: Accounting that God was able to raise him up, even from the dead; from whence also he received him in a figure.
Yes, but the part you're not understanding that I'm pointing to is what Apostle Paul also taught in Romans 4 and Galatians 3 about The Gospel having been preached to Abraham.
All the following Scripture by Apostle Paul is about FAITH on The Gospel of Jesus Christ. It is NOT simply about the idea that Christ would be born through Abraham's seed. Or haven't you understood that the concept of FAITH is not the same thing as SEED?
Rom 4:9-13
9 Cometh this blessedness then upon the circumcision only, or upon the uncircumcision also? for we say that faith was reckoned to Abraham for righteousness.
10 How was it then reckoned? when he was in circumcision, or in uncircumcision? Not in circumcision, but in uncircumcision.
11 And he received the sign of circumcision, a seal of the righteousness of the faith which he had yet being uncircumcised: that he might be the father of all them that believe, though they be not circumcised; that righteousness might be imputed unto them also:
12 And the father of circumcision to them who are not of the circumcision only, but who also walk in the steps of that faith of our father Abraham, which he had being yet uncircumcised.
13 For the promise, that he should be the heir of the world, was not to Abraham, or to his seed, through the law, but through the righteousness of faith.
KJV
That FAITH which Abraham had, before the law, wasn't about 'seed'. It was about the SAME FAITH that ALL BELIEVERS ON JESUS CHRIST HAVE, and that means The GOSPEL.
Gal 3:6-9
6 Even as Abraham believed God, and it was accounted to him for righteousness.
7 Know ye therefore that they which are of faith, the same are the children of Abraham.
8 And 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.
9 So then they which be of faith are blessed with faithful Abraham.
KJV
Gal 3:14
14 That the blessing of Abraham might come on the Gentiles through Jesus Christ; that we might receive the promise of the Spirit through faith.
KJV
That above verse is very, very important in differentiating the matter.
Gal 3:29
29 And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise.
KJV
According to what Promise? According to the GOSPEL PROMISE BY FAITH, not by seed.
That means that The Gospel of Jesus Christ was literally... preached to Abraham, and THAT is what Abraham believed, BY FAITH, and that is HOW God imparted righteousness to Abraham, because of his FAITH.
That the Promise by FAITH would continue to be known... through Abraham's seed, is a secondary issue, and involves the chosen duties God gave to Israel to benefit all nations with The Gospel. Yet only a small 'remnant' of old Israel believed. Thus Apostle Paul does NOT confuse those two separate issues in those Romans 4 and Galatians 3 Chapters. God's Promise of The Spirit by Faith is one thing, but His Birthright blessings and His duties for the chosen 'seed' involving the 'care' of The Gospel of Jesus Christ is another thing.