Romans 3:29

Is God the God of Jews only? Is he not the God of Gentiles too? Yes, of Gentiles too,

(v29, NIV)

Clearly God is both God of the Jews and God of the Gentiles. God is not only the God of the Jews. This had been a prominent belief at the time because Israel was God's chosen people back in the Old Testament. This is true, but we also read in Ephesians about this mystery that was made known to Paul. The mystery is that the Gentiles are fellow heirs together with Israel through the gospel. In addition, Paul speaks about this in Galatians, explaining it as children and heirs. God is not only the God of the Jews but also the God of the Gentiles. Why does Paul bring this up in this passage? Paul was just talking about excluding boasting on the basis of faith as opposed to the observance of the law. The law was given to the Jews but was not given to the Gentiles. However, boasting is excluded on the basis of faith and we know that justification comes through faith in Jesus. Paul has done away with excuses regarding the law and fairness in the previous chapters. Even though the law was given to the Jews, those without the law even have it written on their hearts. In addition, their conscience bears witness to themselves. But at the same time, Jews have an advantage in their being given of the law. Even so, God is God of both Jews and Gentiles. In justification he justifies both by faith through Jesus Christ and not by observance of the law where only one of the two were given it.