Psalm 23:4 says, "Even when I walk through the darkest valley, I will not be afraid because You are close beside me. Your rod and you staff protect and comfort me. 

King Saul looked at David, the young shepherd boy and told him "Don't be Ridiculous" when David offered to take on the mighty Goliath. What Saul failed to understand is that David was empowered by the Holy Spirit to take on the evil giant. Everything about Goliath represented sin and the evil that is in this world, and everything about David represented Jesus, our shepherd who was sent to save what was once lost.