1 Peter
One of the main ideas in this book is that being a Christian means that you suffer a lot. The question is “how should one suffer?” The answer is: suffer like Jesus did. He is a good example to follow in everything.
2 Peter
All of these books have good nuggets that I don’t have time to draw your attention to, but an important one here is at the end of chapter 1, where Peter tells us that Scripture comes from God. That’s why the Bible is God’s Word and not just another book. This book focuses mostly on false teachers and the coming judgment. One of the most deadly things for a church is false teachers, because they take the people away from what God says (in his Word). But judgment is coming and so it is important to stay faithful to God and live a holy life.