Genesis 12 where God promises blessing. It continues in chapter 15 where God promises offspring, and then is officially cut in Genesis 17 where God promises to be the God of Abraham and His offspring, promising him eternal blessing and an inheritance in the land of Canaan forever.
"That's all well and good," you may say, "but what about me? I'm not a physical offspring of Abraham. Why is this a promise for me?" The answer comes from how we need to read our Bibles as New Testament believers.
The Bible is one story, given by one divine Author, written to focus on Christ. Jesus Himself showed the disciples this after He rose from the dead (Luke 24:27, 45). This is also affirmed in 2 Corinthians 1:20 as we read that all the promises of God find their "Yes" in Christ. The scriptures these passages point to are not the New Testament Gospels and Epistles, but the Old Testament writings in the Law and Prophets. All of scripture is united in this singular story of redemption, and it would be foolish of us to read our Old Testaments without keeping the New Testament in mind. Christ said the same thing to the Jews in John 5, saying they should have known about Him as they searched the scriptures because the scriptures testify about the Christ (John 5:39).
That is what's wonderful about the Bible. When we read it with the end of the story in mind it changes everything. As one of our favorite children's Bibles says, every story whispers His name.* This is what we love about some of our favorite books or movies. Once the big twist is revealed at the end we rush to watch it again or reread it keeping the twist in mind. It would take away from the truth of the entire story to ignore the fact that the little boy can see dead people or that Darth Vader is Luke's father or that Harry actually is a horcrux himself! (sorry for the spoilers, but I think you get the point) Back to our passage...
As we read the NT, we come to the book of Galatians where Paul reveals to us what God was really talking about when he spoke to Abraham 2,000 years earlier. He writes in Galatians 3:16, "Now the promises were made to Abraham and to his offspring. It does not say, 'And to offsprings,' referring to many, but referring to one, 'And to your offspring,' who is Christ." This simple verse changes everything. No longer are the promises focused on national ethnic Israel. We see now that the promises find their "Yes" in Christ! He is the point of God's promise to Abraham. He is the blessing that all the families in the earth will enjoy. To remove all doubt, Paul concludes the chapter by writing, "If you are Christ's, then you are Abraham's offspring, heirs according to promise." (Galatians 3:29)
Oh the greatness of God that He would expand His promises to include all those in Christ! Gentiles are not second class citizens in the economy of God. There isn't a higher blessing reserved for those whose blood runs Israeli blue. Jew, Gentile, slave, free, male, female- all are one under the banner of Christ Jesus! (Galatians 3:28)
There are still a lot of unanswered questions regarding the role of Israel which I don't have time to get into now. Needless to say, there are volumes that do speak to this if you are interested. I would encourage you to look at your Old Testament through the lens of the New. Let the NT scriptures interpret your understanding of the OT, and take great joy that you are now a child of the promise! When it comes time to sing "Father Abraham", know that you are one if his sons or daughters, and sing it loud and proud. We are heirs in Christ and a beneficiaries of all the riches that come with being an adopted child of the King.
*from The Jesus Bible Storybook