Why does the Bible contrast Jews and Gentiles?

In Ephesians 2, Paul emphasizes the historical divide between Jews and Gentiles, stating that Gentiles were once 'without Christ, being aliens from the commonwealth of Israel' (Ephesians 2:12). However, through Christ, this division is overcome. Verse 13 announces, 'But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ,' signaling that all who trust in Christ, regardless of their background, are brought into a single redeemed community. This unification illustrates God's plan for redemption to embrace all of humanity through faith in Jesus.