17:16-19
This charade went on for forty days and the impasse would eventually be broken by David. This began in a n inauspicious way. Jesse told David to take some bread to his brothers in the camp, and to take ten cheeses to their commander. Jesse also wanted some assurance that his sons were OK. His reference to them “fighting against the Philistines” indicates that Jesse was unaware of the nature of the “battle”, and he had no idea that David would be the one to finish the matter.
17:20-24
So David set off, leaving the flock in the care of a shepherd. So David still made sure that the flock were looked after properly. “He reached the camp as the army was going out to its battle positions, shouting the war cry”. It would be more accurate to say their “non-battle positions”. The charade was continuing. David left the supplies he had brought and went to his brothers to see how they were. While he was doing this Goliath appeared. When the Israelites saw Goliath they simply fled. But this time David heard and saw what was happening.