The words “blessed be…God” are well-known from Israel’s liturgy of praise for God in the temple (e.g., Psalm 41:13; Psalm 72:18; Psalm 89:52; Psalm 106:48; each of these forms the concluding words of books of the Psalter). The reason Israel was to bless God was encapsulated in the material mentioned in earlier psalms, namely, his mighty works of mercy to his people. Peter hooks on to this praise because he is so overwhelmed by God’s mercy as detailed in 1 Peter 1:3–12.
3 Blessed be the God and Father of our Lord Jesus Christ! According to his great mercy, he has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead,