Peter wrote his second letter to encourage believers to stand firm in their faith until death. He emphasized three key points: 1. Faith comes from God, not by our own works, and helps believers escape corruption. 2. Believers must add virtues like knowledge, self-control, and love to their faith in order to progress spiritually. 3. Living according to one's faith is important, as denying it could put salvation in jeopardy. Peter wanted to remind believers of these things even after his death, which he did not fear as he believed in the resurrection at Jesus' return.