I have struggled all of my life with low self esteem. For many years I had negative tapes playing in my head: "You're ugly; you're worthless; you're fat, etc." About three years ago, after a long process of prayer and devotion, God erased those tapes. However, I still struggle. And now God has called me to a position of public ministry and I find that the biggest obstacle is this lack of self worth. It is ultimately a very selfish thing--focusing on myself rather than on God and what He can do.
So, with Gideon, I can identify with his discouragement and lack of faith in God's ability to use Him. Again and again, God chooses people who really aren't equipped to do what He is calling them to do (Moses, David, the disciples) and demonstrates that His power is greater than anything that we may think we can do on our own. All that is needed is faith and trust in God and a willingness to follow His will for us.
"That is why, for Christ's sake, I delight in weaknesses, in insults, in hardships, in persecutions, in difficulties. For when I am weak, then I am strong." 2 Corinthians 12:10