What does it mean to fear God?

The angel of the LORD encamps around those who fear him, and he delivers them...Fear the LORD, you his holy people, for those who fear him lack nothing. The lions may grow weak and hungry, but those who seek the LORD lack no good thing.
Psalm 34:7;9-10

Psalm 34 is all about fearing God. It includes the rewards for fearing God and the punishment for not doing so. This might make you wonder what exactly, it means to fear God. First, I want to be sure everyone understand that fear of God is a positive thing. Here are a few examples of this:

• Exodus 1:17: Because the midwives feared God, they obeyed him instead of Pharaoh by sparing the Hebrew babies
• Exodus 9:29-31: Pharaoh brought disaster on his nation because he did not fear God
• Exodus 18:21: Moses was to choose leaders who feared God and wouldn't take bribes
• Exodus 20:20: Moses told the Hebrews that they should fear God to keep them from sinning 
• Leviticus 19:14; 32: The law says fear of God as a reason to treat the disabled and elderly well
• 2 Corinthains 7:1: Paul says to work toward complete holiness because we fear God

Fear of God is obviously not a bad thing, but is is indeed, fear, not a holy reverence.

Do not be afraid of those who kill the body but cannot kill the soul. Rather, be afraid of the One who can destroy both soul and body in hell.
Mathew 10:28

Jesus says so himself. The bible does say over and over again to fear not, but what Jesus is saying is that shouldn't fear creation, but the creator. The creator is the one who decides if we go to heaven or to hell.

Now all has been heard; here is the conclusion of the matter: Fear God and keep his commandments, for this is the duty of all mankind. For God will bring every deed into judgment, including every hidden thing, whether it is good or evil.
Ecclesiastes 12:13

Serve the LORD with fear and celebrate his rule with trembling. Kiss his son, or he will be angry and your way will lead to your destruction, for his wrath can flare up in a moment. Blessed are all who take refuge in him.
Psalm 2:11-12

I've talking on God's wrath before, so I'll get to the point. The point is 1 John 4:18 says "There is no fear in love. But perfect love drives out fear, because fear has to do with punishment. The one who fears is not made perfect in love." So this may seem like a contradiction. How can we love and fear God at the same time? This verse says we can't.
Well Jesus is the best example of fear and love working together. He warned us over and over again to not fear men, but to fear God. He spoke lovingly, but frankly to all people because we all need to face our sin and repent. But he also demonstrated love beyond human understanding

My command is this: Love each other as I have loved you. Greater love has no one than this: to lay down one's life for one's friends.
John 15:12-13

Photo Credit:
http://survivingsurvivalism.com/fear.htm

Sources:
http://www.christianitytoday.com/biblestudies/bible-answers/spirituallife/what-does-it-mean-to-fear-god.html