How do we know that God's grace includes both Jews and Gentiles?

In the prophecies of Zechariah, we observe a clear indication that God's saving grace encompasses both Jews and Gentiles. Zechariah speaks of a remnant, signifying that though many may forsake the Lord, a chosen group from the Jews and all nations will be brought to faith. Paul's epistles, particularly Romans 9, 10, and 11, affirm this unity of God's elect, illustrating that faith in Christ transcends ethnic boundaries. The promise that those who are 'called'—whether they are from the house of David or the inhabitants of Jerusalem—will look upon the one they have pierced, establishes a foundation for the inclusion of Gentiles into God's redemptive plan.