As David returned from the slaughter of the Philistine, Abner took him, and brought him before Saul with the head of the Philistine in his hand.
In applying this story, I believe it is legitimate to see Goliath as representing the many enemies that frustrate individual believers as we seek to live for God. However, I believe primarily the application deals with defeating those enemies bent on defeating and destroying God’s people en masse. Contemporary movements designed to discredit God and remove Christianity from a land are what Goliath personifies.