If we do not know God’s word, or even part of His word, it could lead to arrogant self-opinion. For example, Paul explained that the Jews have been removed from God’s tree, and the Gentiles have now come into the church.
However, he said, “For I do not desire, brethren, that you should be ignorant of this mystery, lest you should be wise in your own opinion, that blindness in part has happened to Israel until the fullness of the Gentiles has come in” (Romans 11:25).
Some Gentiles might begin to think more highly of themselves than they ought to think, but Paul revealed what God is doing with the Jews and the Gentiles, and it is not because the Gentiles are greater than the Jews, nor are the Jews greater than the Gentiles.
Israel had her time; the Gentiles have their time; then we shall all have our time.