How do we know that Gentiles are included in God's plan?

The Bible demonstrates that Gentiles are included in God's redemptive plan primarily through the ministry of the Apostle Paul. In Acts 13, Paul explicitly turns to the Gentiles after some Jews reject the Gospel, stating that it was necessary to first speak to the Jews, but now the message is extended to the Gentiles because God had commanded him to be a light for them. In Ephesians 2:13-14, Paul articulates how Gentiles, who were once separate from God's promises, are now brought near by the blood of Christ, proving that all nations are part of God's eternal purpose.