Peter says God caused believers to be born again to a “living hope” through the resurrection of Jesus Christ from the dead (1 Peter 1:3). The hope is tied to God’s mercy and Christ’s resurrection as its basis (1 Peter 1:3).
In 1 Peter 1:3–5 the writer calls for praise to God because God has acted out of great mercy to give believers a new beginning and a “living hope,” grounded in Jesus’ resurrection. This new hope points toward an inheritance that cannot decay, be stained, or lose its brightness, and it is kept secure. These verses begin the main body of 1 Peter right after the opening greeting (1:1–2). The letter starts by naming God’s action and its results before turning later to the readers’ difficulties and daily conduct.
These verses open the main message of the letter with praise directed to “the God and Father of our Lord Jesus Christ.” The reason given is what God has done “according to his great mercy”: God has brought about a new beginning (“born again”) that results in “a living hope,” and this hope is anchored in Jesus’ resurrection.
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with 1 Peter 1:3, then read the surrounding section so the answer stays connected to the passage's flow.
3Blessed be the God and Father of our Lord Jesus Christ, who according to his great mercy became the father of us again to a living hope by the resurrection of Jesus Christ from the dead,