The bible addresses all the problems that we face that are in this world. There is only one answer to these problems. God has made man to rule the earth. When man is frustrated it is because he is facing opposition to subduing the earth. So God has placed a government in the heart of man.

This is why God worked with a nation to establish His kingdom upon this earth. From the beginning God created man for the purpose of showing that He is a saving God. God establishes His salvation on this earth through overcoming all opposition to His kingdom. God has placed His kingdom in mans heart.

When God created the heavens, earth and mankind He told Adam to name the animals. As we read further in the book of Genesis we see man creating a government and culture. When God established the nation of Israel He established the nation through circumcision. Circumcision was the birthright to receiving all of the privileges of  citizenship. Circumcision was a sign that God would be faithful to the Nation through His covenants. But not all of Israel were faithful. Even tho they were chosen to be included in receiving the benefits of Gods covenants they were not part of Gods elect within the nation. "Jacob I loved, Esau I hated" ..."Not all Israel are Israel"So God had a remnant of people within the nation who enjoyed His fatherly care. So salvation has always been Gods display of His covenant faithfulness that cannot fail because He picked His own for Himself.

But salvation has never been according to race..sex or color. From the beginning of time God has purposed to bring salvation to Israel so that it would spread to the nations. We read about this expansion in a limited way when Israel went into exile. The gospel was spread as Israel was in bondage to the surrounding nations. "Then it was said among the nations the Lord has done great things for them and we are filled with joy."

But it wasnt until we get to the NT and the fall of Jerusalem that we find a serious spread of the gospel to the ends of the earth. And yet Gods salvation has never changed. It has always been according to His special choice of His people. But we find these expressions of the gospel spreading to the ends of the earth in the NT in the words all, everyone, the world etc.