That is how it is with the promises God made to Abraham and his descendant. The promises were not made to many descendants, but only to one, and that one is Christ.
You are really the ones God told his prophets to speak to. And you were given the promise that God made to your ancestors. He said to Abraham, "All nations on earth will be blessed because of someone from your family."
God promised Abraham and his descendants that he would give them the world. This promise wasn't made because Abraham had obeyed a law, but because his faith in God made him acceptable.
Everything depends on having faith in God, so that God's promise is assured by his great kindness. This promise isn't only for Abraham's descendants who have the Law. It is for all who are Abraham's descendants because they have faith, just as he did. Abraham is the ancestor of us all.
They are the descendants of Israel, and they are also God's chosen people. God showed them his glory. He made agreements with them and gave them his Law. The temple is theirs and so are the promises that God made to them.
What is the use of the Law? It was given later to show that we sin. But it was only supposed to last until the coming of that descendant who was given the promise. In fact, angels gave the Law to Moses, and he gave it to the people.
Long ago the Scriptures said that God would accept the Gentiles because of their faith. That's why God told Abraham the good news that all nations would be blessed because of him.
They are no longer part of Christ, who is the head of the whole body. Christ gives the body its strength, and he uses its joints and muscles to hold it together, as it grows by the power of God.
It doesn't matter if you are a Greek or a Jew, or if you are circumcised or not. You may even be a barbarian or a Scythian, and you may be a slave or a free person. Yet Christ is all that matters, and he lives in all of us.