We ought to fear God because we are commanded to fear God. He is God in every right and worthy of our fear. We do well to fear God because there are immediate and eternal blessings for those who do so. It is an intelligent and strategic move to fear the Omnipotent One. Fear of the LORD is also just simply the natural response when we see Him as He truly is. He is fearsome. Everyone who has caught a glimpse, even just of His robes and backside, has lost all decorum and fallen on their face in terror and wonder. We will fear Him if we are rightly seeing the real God. But there is another reason, if you will, to fear God. We were ransomed with precious blood.
I am trying to imagine returning dirty and hungry but unharmed to the castle, to the bounty and the privilege and to the warmth of the Father's arms with one giant thing missing: the presence of the Prince, the firstborn Son. I am vainly trying to attain insight as to how one would carry out the rest of her days after cheating torturous death by the torturous death of her elder brother. How does she properly console her Father, the King? How does she ever measure up to be worth all that sacrifice for the kingdom? Of course, the analogy is brittle and cannot hold much weight, let alone the glory of the resurrection, but we must consider the breakup our sin has cost the Trinity. There is no way to fathom the agony that was endured by the Godhead when sin separated Christ from Father and Spirit for the first and only time in all of an otherwise eternity of oneness.
The Son Himself is most probably best suited to inform our lifestyle from here on out. "'I say to you, My friends, do not be afraid of those who kill the body and after that have no more that they can do. But I will warn [show] you whom to fear; fear the One who, after He has killed, has the authority to cast into hell; yes, I tell you, fear Him! Are not five sparrows sold for two cents? Yet not one of them is forgotten before God. Indeed, the very hairs of your head are all numbered. Do not fear, you are more valuable than many sparrows'" (Luke 12:4-7). The ransom Himself has told us how to live.
Christ's words follow the same progression we see in all of scripture: fear of God that leads to release from the fear of man. We are instructed to live in the fear of God. This is important to call attention to, because it is terribly easy to assume that Jesus did away with fear. But Jesus confirms His message for those who may be hard of hearing or incredulous. Yes, I am actually telling you to fear God (exclamation point)! He follows this command with the reassurance of why this works, why this is the only way it works. We are invaluable to God. He has vested all His interest in us. He has bought us with absolutely everything of value, and He has made sure He will never have to do that again (1 Peter 3:18). We aren't going anywhere. The King claimed us, bought us, cleaned us up and made us heirs. He has tally on our hairs and our tears and our thoughts (Psalm 56:8, Psalm 119:1-4). He has achieved the joy set before Him, and nothing in all of creation has the power to snatch us away from His life-grip (Romans 8:35-39). We honor His sacrifice by remaining in Him. We remain in Him by fear that keeps us in a state of obedience to absolutely whatever He commands. There is nothing else to fear. It is finished. We are home. We are His.