What is the new nation? Again Peter, who was given the keys of the kingdom, made one of the clearest pronouncements to Christians.
But you are a chosen race, a royal priesthood, a holy nation, a people for his own possession, that you may proclaim the excellencies of Him who called you out of darkness into His marvelous light. Once you were not a people, but now you are God’s people; once you had not received mercy, but now you have received mercy. (1 Peter 2:9-10)
Originally these Old Testament terms—chosen people, holy nation, God’s possession—were spoken of Israel as God’s special nation. As an Israelite, Peter knew full well the significance of these terms. Yet, by inspiration, he applied them to Christians as the new, spiritually defined nation. The old nation was physically defined as the fleshly descendants of Abraham, Isaac and Jacob (Israel). But the new nation has a spiritual basis since each member has become a spiritual son of God and of Abraham.
For in Christ Jesus you are all sons of God, through faith. For as many of you as were baptized into Christ have put on Christ. There is neither Jew nor Greek, there is neither slave nor free, there is no male and female, for you are all one in Christ Jesus. And if you are Christ’s, then you are Abraham’s offspring, heirs according to promise. (Galatians 3:26-29)
“If you are Christ’s, then you are Abraham’s offspring.”
After this passage about spiritual sonship, Galatians moves on to discuss the New Covenant. Galatians 4:24-31 identifies Christians as children of Sarah. As for Jews who persist in the Old Covenant, they are children of Hagar. Based on such truths, Galatians shows the irrelevance of circumcision, and ends with a greeting that calls Christians “a new creation” and “the Israel of God” (Galatians 6:15-16 cf. Romans 2:28-29; 4:12-16; 9:6-8).
Jewish believers in Christ were the first citizens of the new nation. The New Covenant was with the people of Israel and Judah who knew the Lord (Hebrews 8:8-11). Those Israelites learned from its terms that God wanted non-Jews to be included also. “So then you [Gentile Christians] are no longer strangers and aliens, but you are fellow citizens with the saints and members of the household of God” (Ephesians 2:19). Ephesians calls this same combined group the “body” and the “church.” Therefore, another word for God’s new nation is the church.