God promised to bless Abraham and make him a blessing to all nations. He repeated this promise to his son, Isaac (Gen. 26:5, 6) and to his grandson, Jacob (Gen. 28:12–14), as well. God chose Abraham and his descendants so they could not only know Him, but also make Him known. Years later God sent Moses to command Pharaoh, “Let my people go!” But why? “That they might worship Me!” (Ex. 4:23). Their worship of the one true God was to be a witness to all nations of God’s power to save.
This world is under the rule of the god of this age, the devil. But God’s redemptive mission has begun. King Jesus came to set His people free to live and to praise God’s glory. His liberated people are His “special treasure.” As His loyal subjects they are a “kingdom of priests” with the priestly duty of proclaiming the gospel of God, so that the nations might become an offering acceptable to God, sanctified by the Holy Spirit (Rom. 15:16).