The people of God is a term for the group of people who believe in God. In the Old Testament, a key part of Israel's faith was that they became the people of God because he chose them to be his special possession (Exodus 6:6–7; 19:5; Deuteronomy 7:6; 14:2; 26:18). This idea is connected to the concept of the covenant between God and Israel (Leviticus 26:9–12). When the Bible talks about the covenant between God and Israel, it means the agreement where God promised to bless and protect the people of Israel, and they promised to follow God's laws and worship only him.
When the prophets preached about God's judgment that could lead to complete destruction, they also shared visions of God rebuilding and recreating his people (Jeremiah 32:37; Hosea 2:1, 23; Ezekiel 11:20; 36:28). After the exile, Judaism developed the idea that only the future Israel, the final community led by the Messiah (God's chosen leader), would truly be the “people of God” in the fullest sense.
The New Testament shows in several passages that the early church understood itself to be this future people of God. The clearest example is found in 1 Peter 2:9: “But you are a chosen people, a royal priesthood, a holy nation, a people.” The expressions “royal priesthood” and “holy nation” come from Exodus 19:6. This verse describes Israel's role as priests to the world, participating in God's reign. The original people of God were to declare His mighty acts (Isaiah 43:20–21). The new people of God must proclaim the one who brought them from darkness to his marvelous light (1 Peter 2:9).