1 Peter directly quotes Isaiah’s contrast between fading human life and the enduring word of the Lord, then identifies that enduring word with the gospel preached to his readers.

James and 1 Peter both connect divine begetting/new birth with God’s word and contrast human frailty with enduring divine action. The approved evidence supports the relationship at its existing confidence level without requiring a stronger quotation, fulfillment, or typology claim than the texts warrant.

New birth through the enduring word flows directly into the newborn-child image of craving pure milk and growing, making 1:23–2:3 one continuous birth-and-growth movement.

Isaiah 40:6-8 → 1PE 1:24-25: the later passage directly quotes Isaiah.