שמואל א, פרק י״ז, פסוק י״ד

The military conflict required manpower, but age dictated who was called to the front lines. As the youngest of his family, David was left behind while his older brothers were drafted into the army. The primary approach among commentators is that his youth simply disqualified him from military service, keeping him away from the battlefield [מצודת דוד, ביאור שטיינזלץ].

This family dynamic explains a sudden shift in David's daily life and his absence from the royal court. Previously, he had spent time in the king's palace, playing music to soothe him [רש״י]. However, when his three oldest brothers left to join the king's army, David was forced to change his routine. He had to leave the palace and return to his father's house to take over the responsibility of shepherding the family's flock. Because he was back home tending the sheep, he was not present at the military camp to hear the taunts of Goliath the Philistine [מלבי״ם].

Looking at the situation from a different angle, this arrangement reveals a hidden layer of tension. The stark contrast between the youngest staying behind while the older brothers went to war suggests a deep-seated resentment. Even though David was the youngest, he had already been destined for greatness and favored over his older siblings. This preference sparked jealousy among the brothers, coloring the reality that they were the ones who marched off to follow the king [אלשיך].