What does Romans 15:11 mean?
Paul is continuing to provide quotations from Old Testament Scriptures to support his teaching that Christ came to serve the Jews both to fulfill God's promises to them and to cause the Gentiles to glorify Him.He now quotes almost directly from Psalm 117:1. David calls these people "the nations," a common Old Testament reference to all non-Jewish people: the Gentiles. Again, Paul is showing that God planned all along for Gentiles and Jews to praise the Lord together as they came to Him through faith in Christ.
The verse following Paul's quotation, Psalm 117:2, shows the Gentile nations praising the Lord for His steadfast love and faithfulness. This follows a major theme of New Testament teaching: that the gospel applies to all people and cultures, throughout all of mankind (Galatians 3:28–29).