What is the one thing that cuts us off from heaven? The answer is unbelief. Not trusting God. Not living “by faith in the Son of God who loved us and gave Himself for us” (Gal. 2:20). So what does [1 Peter 1] verse 5 mean then when it says we are “protected [from losing our final salvation] by the power of God through faith.” It means that God’s power protects us for salvation by sustaining our faith. The only thing that can keep us from heaven is forsaking our faith in Christ, and turning to other hopes, other treasures. So to protect us God prevents that. He inspires and nourishes and strengthens and builds our faith. And in doing this he secures us against the only thing that could destroy us; unbelief, lack of trust in God.