Armour-bearers were meant to be skilled in battle, close personal attendants and advisors to their lord (see Judges 9:54; 1 Samuel 14:1; 1 Samuel 31:4–6). They accompanied the king when he went to war. The fact that David was allowed to go back home at certain times (see 1 Samuel 17:1–58) suggests that Saul had more than one armour-bearer.1 David’s inclusion in this group affirms that he was a regular attendant of Saul2 and not necessarily responsible for carrying his armour.
21 And David came to Saul and entered his service. And Saul loved him greatly, and he became his armor-bearer.