What does 2 Peter 3:18 mean?
Verses 17 and 18 are the conclusion of Peter's letter and should be taken together. These words summarize Peter's letter, and include both a warning against being misled by the false teachers and an encouragement to keep growing in Christ. Specifically, Peter urges his readers to grow in two areas: The grace of Jesus, and their knowledge of Him.To grow in grace does not mean to get more and more of God's grace, necessarily. Grace, by definition, is unearned, unworked for. By His grace, God has forgiven our sins and given us full rights as His children in Christ. We can't get more of that. But living under the grace of Jesus provides us a huge opportunity to grow spiritually stronger and deeper. Peter wrote in chapter 1 that we are not missing anything we need to lead the life God calls us to. Now it's time to do it.
One way we grow under the grace of God is to grow in our knowledge of Christ. This implies two ideas. One of these is knowing more and more about Christ in our minds: information. The other is getting to know Jesus better and better in our relationship with Him. Both contribute to making us more productive servants (1 Peter 1:8).
Peter describes Jesus as both our Lord and our Savior. To really know Him, we must continue to grow in our understanding of what it means to live in relationship to Jesus as Lord and as Savior.
And we, like Peter, will reach a single conclusion: Jesus is the one who is due glory both in this moment and forever.