The exhortation of 1:13 provides the keynote of this section, as Peter tackles the unspoken question, How can I have a faith like that? He mentions faith four times in 1:3–9, and it would be very possible for an oppressed, isolated believer to feel that the faith described is too high to attain. Peter sets out in this section to show what the roots of such a faith are—and it turns out that the way we think is absolutely vital.

Peter’s sudden introduction of “the prophets” (1:10–12)—probably shorthand for the whole Old Testament—is at first sight surprising. But there are two excellent reasons for their appearance. First, the prophets back up what Peter writes about the foreknowledge of God the Father in 1:2. God announced centuries ago his intention to save the followers of Jesus. It was…