Why did Israel reject the Old Testament covenant promises according to Paul in Acts 28?
Paul explained that all the Old Testament covenant promises had been presented to Israel, but Israel rejected them when they crucified their Messiah. The Jewish leaders in Rome then left Paul in discord and disagreement because they could not believe. Consequently, the salvation of God was sent to the Gentiles, who would hear it.
Les teaches that by Acts 28 Paul had finished his missionary journeys and was imprisoned in Rome. He called the Jewish leaders there and reviewed how all the Old Testament covenant promises had been presented to Israel, but they rejected them when they crucified their Messiah. They departed in discord and disagreement, unable to believe. Paul then declared that the salvation of God is sent to the Gentiles, and they will hear it. Les notes this does not mean all Gentiles are saved, but they will hear, leaving the world guilty and without excuse, as Romans 1 says. With Paul's apostleship, the calling out into the body of Christ becomes predominantly Gentiles, though Jews can still believe as exceptions, a complete flip-flop from the earlier Jew-only emphasis with some Gentiles.