דברי הימים א, פרק י״א, פסוק ו׳

David faces the difficult task of conquering a fortified city and issues a bold challenge to his men to inspire a decisive victory. He calls upon his warriors to break into the city and crush the Jebusite resistance, likely by exploiting a specific weak point in the defenses that would allow the army to infiltrate [ביאור שטיינזלץ]. A significant reward is promised to the first soldier who bravely leads the charge into battle [מצודת דוד] and successfully shatters the enemy lines [מלבי״ם, ביאור שטיינזלץ].

The prize for the hero who completes this dangerous mission is a high-ranking appointment, promising the dual titles of head and officer [ביאור שטיינזלץ]. Joab the son of Zeruiah accepts the challenge and is the first to breach the city. However, the record of his reward notes only that he became a head, leaving out the title of officer. This subtle detail highlights his prior standing. Joab already held the position of an officer as the commander of the army, making a reappointment to that role unnecessary. Instead, his victory earned him an additional promotion, elevating him to the role of head in charge of leading the city itself [מלבי״ם].