Therefore know that only those who are of faith are sons of Abraham. – Galatians 3:8
The emphasis is clear. Paul made an important point, and he wanted each one of his readers to understand it. Since Abraham was made righteous by faith and not by works, Abraham was therefore the father of everyone who believes God and is accounted righteous. This was a strong rebuke to the Jewish Christians who tried to bring Gentile Christians under the law. They believed they were superior because they descended from Abraham and observed the law. Paul said that the most important link to Abraham was not the link of genetics and not the link of works, but it is the link of FAITH.
This would have been a shocking change of thinking for these particular opponents of Paul. They deeply believed that they had a standing before God because they were genetically descended from Abraham. At that time, some Jewish Rabbis taught that Abraham stood at the gates of Hell just to make sure that none of his descendants accidentally slipped by. John the Baptist dealt with this same thinking when he said, Do not think to say to yourselves, “We have Abraham as our father.” For I say to you that God is able to raise up children to Abraham from these stones (Matthew 3:9). Paul knocked down their blind reliance on genetic relation to Abraham and showed that what really mattered was faith in Jesus.
It’s the same today when people believe God accepts them because they come from a Christian family. God is a Father, not a grandfather; everyone must have their own faith in God. This was a great comfort to the Gentile Christians who were regarded as “second class Christians” by others. Now they could know that they had a real, important link to Abraham and could consider themselves sons of Abraham by faith and not blood.
Sadly, Christians have taken this glorious truth and misapplied it through the centuries. This has been a verse that many claim in support of replacement theology – the idea that God is finished with the people of Israel as a nation or a distinct ethnic group, and that the Church spiritually inherits all the promises made to Israel. Replacement theology has done tremendous damage in the Church, providing the theological fuel for the fires of horrible persecution of the Jews. If Galatians 3:7 were the only verse in the Bible speaking to the issue, there might be a place for saying that the Church has completely replaced Israel. But we understand the Bible according to its entire message, and allow one passage to give light to others.
For example, Romans 11:25 (hardening in part has happened to Israel until the fullness of the Gentiles has come in) states clearly that God is not finished with Israel as a nation or a distinct ethnic group. Even though God has turned the focus of His saving mercies away from Israel on to the Gentiles, He will turn it back again. This simple passage refutes those who insist that God is forever done with Israel as Israel, and that the Church is the New Israel and inherits every promise ever made to national and ethnic Israel of the Old Testament. We are reminded of the enduring character of the promises made to national and ethnic Israel (such as Genesis 13:15 and Genesis 17:7-8). God is not “finished” with Israel, and Israel is not “spiritualized” as the church. While we do see and rejoice in a continuity of God’s work throughout all His people through all generations, we still see a distinction between Israel and the Church – a distinction that Paul understands well.
All who put their faith in Jesus Christ are sons of Abraham; but Abraham has his spiritual sons and his genetic sons, and God has a plan and a place for both. Yet no one can deny that it is far more important to be a spiritual son of Abraham than a genetic son. Why gain the whole word just to lose your soul?