make you jealous … make you angry: This quotation from Deuteronomy 32:21 describes God’s punishment of Israel for worshiping other gods (idolatry).
In Paul’s time, Israel was still guilty of idolatry. This was because many people treated the law as more important than God himself. As a result, God used the Gentiles (people who were not even considered a nation) to make Israel jealous and angry. Paul explains this idea more fully in Romans 11:12–32.