We see that doubt causes fear, but we also see a hint of how we can combat that fear and get it under control. As long as Peter kept his focus on Christ, he could do the impossible, but once he began walking by sight, fear gripped him. Under its control, he was no longer able to do the impossible. Even though fear is a natural human emotion, do we control it or does it control us (see Genesis 4:7)?
Hebrews 3:12 warns, "Beware, brethren, lest there be in any of you an evil heart of unbelief in departing from the living God." We need to be on guard against unbelief. The author conjures up a picture of an enemy ready to pounce, advising us that we always need to be at the ready for its attack. We must face it and overcome it.
This verse is not talking about the normal unbelief and its fruit of fear that all people have, for fearfulness is a common human condition. As our Creator, God understands that doubts will creep in now and again. Rather, it speaks of a heart controlled by doubt, by unbelief, leading to fear that can cause us to cut and run from the living God. That kind of heart will drag a person down just as Peter's doubt dragged him down into the waters of Galilee.
The central peril of unbelief is that it breaks the trust that is the basis of our relationship with God. We can see how this worked in Satan. God created him perfect (Ezekiel 28:15), yet somewhere along the line he no longer believed that God was good and doubted that God had his best interests at heart. This doubt about God's love led to the fear that he would not get what he deserved. That fear, born of his unbelief and doubt, led to his rebellion and the most glaring example yet of departing from the living God.
Does God have our best interests at heart? Jeremiah 29:11 says, Yes! "For I know the thoughts that I think toward you, says the LORD, thoughts of peace and not of evil, to give you a future and a hope." As the old saying goes, this is straight from the horse's mouth—from the highest Authority in the universe. The only question is do we believe it with every fiber of our beings?