"...but David entered the Valley of Elah with a God-dominated, not a Goliath-dominated, imagination. He was incredulous that everyone was cowering before this infidel giant. Weren't these men enlisted in the army of the living God? God was the reality with which David had to do; giants didn't figure largely in David's understanding of the world, the real world.
In the Bethlehem hills and meadows, tending his father's sheep, David was immersed in the largeness and immediacy of God. He had experienced God's strength in protecting the sheep in his fights with lions and bears. He had practiced the presence of God so thoroughly that God's word, which he couldn't literally hear, was far more real to him than the lion's roar, which he could hear. He had worshipped the majesty of God so continuously that God's love, which he couldn't see, was far more real to him than the bear's ferocity, which he could see. His praying and singing, his meditation and adoration had shaped an imagination in him that set each sheep and lamb, bear and lion into something large and vast and robust: God.
His imagination was so thoroughly God-dominated that he couldn't believe what he was seeing and hearing when he walked into Ephesdammim – Goliath terror, Goliath phobia. It was an epidemic worse than cholera, everyone down with Goliath-sickness, a terrible disease of spirit that had Saul and his entire army incapacitated."
- Eugene Peterson (from his book on the life of David called "Leap Over a Wall").