1Pe 2:4-5
"As you come to him, a living stone rejected by men but in the sight of God chosen and precious, you yourselves like living stones are being built up as a spiritual house, to be a holy priesthood, to offer spiritual sacrifices acceptable to God through Jesus Christ."
Christ is the Living Stone — rejected by men (crucified), precious in the sight of God (resurrected). Believers are living stones (lithoi zontes) — not dead stones of a physical temple, but living members of a spiritual temple. The priesthood belongs to all believers — not only to a clerical class.
1Pe 2:9-10
"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."
Four Old Testament titles applied to the Church (cf. Ex 19:5-6): chosen race, royal priesthood, holy nation, people for his own possession. The purpose: to proclaim the excellencies (aretas) of God. The Church is the new Israel — not replacing Israel, but fulfilling Israel’s original purpose as a 'kingdom of priests'.