The story of David and Goliath is one of the most famous stories in the Bible. What’s sad is that most Christians get the application of this story all wrong. Growing up in church I often heard that I was David and I could conquer my Goliath's. Goliath could be sin, Goliath could be a math test, Goliath could be a bully, or Goliath could be a football team. If we trust God as David did WE can conquer our Goliath, but that’s not true.
Correct application of this passage is that Goliath represents our sin, Goliath represents an impossible hurdle. But we are not David in this story. In this story, we are the scared Israelite's hiding from Goliath, unable to defeat the giant and unwilling to face him. So, who is David in this story…JESUS! The fact is that the burden of our sin is too great for us to handle. Jesus came to save us from our sin. The law is impossible for us to uphold, but Jesus fulfilled the law. Our sin was great but Jesus is greater! On our own we will never conquer our sin, we need our warrior God and King, Jesus to save us, to conquer for us! If we trust in Jesus as David did, Jesus will conquer our Goliath!
One other observation is the example of Saul. After David defeated Goliath, God blessed David greatly and that enraged the jealous king Saul. Notice Saul’s heart though. Saul watched David, by faith, slay Goliath but instead of: one realizing that he himself lacked that same kind of faith, two repenting of his faithlessness, and three putting his faith back in God, Saul just became bitter and jealous. This sadly happens too often in our churches today. We see the spiritual success of other Bible believing churches and often become bitter and jealous, bringing up false accusations against the growing and successful church. Instead we should be looking at the heart of our own church, repenting of our sin, and trusting our church with Jesus no matter what changes might occur.