Acts 20:28 → Isaiah 43:21

Paul's charge to the Ephesian elders to shepherd "the church of God, which He purchased [peripoieō] with His own blood" employs the LXX vocabulary of Isa 43:21: "the people I acquired [peripoiēsin mou] for Myself." The term peripoieō/peripoiēsis ("to acquire, gain, make a special possession") appears in Exod 19:5 (LXX) for Israel as God's "special possession" (segullah) and in Isa 43:21 for the people God "formed for Myself." Acts 20:28's application of this possessive-acquisition language to the church — "which He purchased [peripoieō] with His own blood" — identifies the church as the new covenant community that fulfills the role of Israel as God's acquired people. The distinct escalation is in the price of acquisition: where Israel was redeemed from Egypt by the Passover blood (Exod 12), the church is acquired at the infinitely higher price of the Son's own blood.