What does 2 Peter 1:8 mean?
It's important to remember that Peter is writing to Christians here. A challenging idea jumps out from this verse and the one that follows: It is possible for a Christian to be fully equipped for a meaningful life of Christlike goodness, and yet to squander that opportunity. It is possible, instead, to choose to be ineffective and unproductive with that precious gift.This is a sobering thought. This would be something like realizing you've had a superpower all along, and have been wasting it. It would be disastrous to leave that ability unused, pursuing lesser things because they were easier or more immediately attractive. How can a Christian avoid that? Peter says that seeking the qualities he listed in the previous verses, and to have them growing in us, is the way to be effective and productive as people who know the Lord.
Prior verses have shown, though, that this isn't just going to happen to us while we're sleeping, or not paying attention. Peter has commanded us to go to work, to "make every effort," to add these qualities alongside the faith we possess.
2 Peter 1:3–15 urges Christians to understand that they are, right now, fully equipped to lead the life to which God has called them. Since they are equipped, they must use those tools through personal effort. They should strive to add Christ’s goodness and other powerful qualities to their lived-out faith. Growing in those qualities leads to a productive, effective life of knowing the Lord. Lacking Christ’s qualities leads to the opposite. Peter continues reminding the reader of what they already know, in order to keep stirring them up, to ensure they remember all of this after he has died (which will be soon).
Peter begins this brief letter to Christians by reminding them they are not missing anything they need to lead the good and godly lives they are called to. They must work, then, to add to their faith the goodness and qualities of Jesus. This requires effort, unlike eternal salvation which is not based on our work. Those who lack these positive attributes will live as unproductive and ineffective servants of God, nearly as blind as unbelievers and forgetting that their sins are forgiven. Peter, near death, insists that his eyewitness testimony about the transfiguration confirms that the prophecies about the Messiah are true. Jesus is coming back.