In Genesis 21.12, the Bible says,
“But God said to Abraham, ‘Do not let it be displeasing in your sight because of the lad or because of your bondwoman. Whatever Sarah has said to you, listen to her voice; for in Isaac your seed shall be called'” (Genesis 21.12).
God reassured Abraham that
the promises, blessings, and prophecies, would all come through Isaac, the son of Sarah, and not Ishmael, the son of Hagar.
In Romans 9, Paul argued that it is not the children of the flesh that are blessed, but the children of the Spirit, and to prove that he quoted Genesis 21.12, that it was not merely a descendant of Abraham through whom the blessing would come, but it was all according to promise, so that even those born of Isaac according to the flesh are not guaranteed to be children of God,
“…nor are they all children because they are the seed of Abraham; but, ‘In Isaac your seed shall be called'” (Romans 9.7).
Therefore, descending from Abraham does not guarantee one’s entry into the Family of God, nor does it mean descending from Abraham is undesirable, but the Family of God is a matter of the Spirit, that is why Paul argued that it is not simply a matter of descending from Abraham, but the promise to bless all the families of the Earth came through Isaac, showing that it is a matter of the Spirit.
Are you a spiritual descendant of Abraham? Paul wrote,
“There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus. And if you are Christ’s, then you are Abraham’s seed, and heirs according to the promise” (Galatians 3.28, 29).
In the preceding verses, the apostle revealed how to get into Christ,
“For you are all sons of God through faith in Christ Jesus. For as many of you as were baptized into Christ have put on Christ” (Galatians 3.26, 27).
Have you done those things yet?
Related Articles
- Messianic Prophecy Number 10: Gen 18.17, 18 – All the Nations of the Earth Blessed in Abraham (theoldtestamentandthenewtestament.com)
- The Bible In Our World (Lesson 5) (thebiblemeditator.wordpress.com)
- Messianic Prophecy Number 8: Gen 12.3 – All Families Blessed through Abraham (theoldtestamentandthenewtestament.com)
The Old Testament and the New Testament 
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Finally, Paul tells us who the true seed of Abraham is and the nature of that promise. We learned earlier that the Seed of Abraham was singular, one person, i.e. Christ.
Next Paul says, “For you are all the sons of God by faith in Christ Jesus for as many of you as we baptized into Christ have put on Christ. There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female for you are all one in Christ Jesus. And if you are Christ’s then you are Abraham’s seed, and heirs according to the promise.” (Gal. 3:26-29).
Those who accept God by faith and are baptized into Him become a part of that one Seed of Abraham who is Christ . We become one Seed with Christ, not many seeds, but one with Him. As the Seed of Abraham through Christ, we then become heirs/inherit the promise. The promise is salvation in Christ, i.e. the kingdom of God. See the post “Flesh and Blood Cannot Inherit the Kingdom of God.” The true seed of Abraham is Christ and the inheritance is the salvation in him to all nations (families of the earth) who are blessed in Him.
Thanks for your comments, Emily!