“Once, you Gentiles were rebels against God, but when the people of Israel rebelled against him, God was merciful to you instead. Now they are the rebels, and God’s mercy has come to you so that they, too, will share in God’s mercy. For God has imprisoned everyone in disobedience so he could have mercy on everyone.” Romans 11:30-32
Paul is reminding us that we are all sinners in need of God’s mercy. We all have rebelled against God. We all at one time have been disobedient. Without God’s mercy where would we be? It is only because of God’s love that we are His children. “For this is how God loved the world: He gave his one and only Son, so that everyone who believes in him will not perish but have eternal life” (John 3:16) Mercy is a wonderful theme throughout the entire Bible. God has dealt with mankind in leniency and compassion since the beginning, but his expression of mercy was in the person of Jesus Christ. This is because Jesus brought into reality the forgiveness of sins so we could be reconciled to God once and for all. Understanding God’s mercy toward us is what brings us to Christ to be justified by him. God’s kindness and love is what leads us to repentance. Repentance simply means to turn around and go the other way. So when we experience the mercy and goodness of God, we abandon the rebellious direction in which we are walking and turn 180 degrees toward God to follow after Him. When we turn to God and accept his message of grace, we receive his mercy that also brings us into right relationship with Him. This is the good news of the gospel, that we are reconciled to God based on his mercy and grace.
If God used the disobedience of Israel for the good of the Gentiles, He can also use the mercy shown to the Gentiles for the mercy of Israel. The idea is that God has shut up both Jew and Gentile into custody as lawbreakers. God offers mercy to these prisoners, based on the person and work of Jesus Christ.