1 Samuel 30:23-25

23Then David said, “You must not do so, my brothers, with what the Lord has given us, who has kept us and delivered into our hand the band that came against us. 24And who will listen to you in this matter? For 1as his share is who goes down to the battle, so shall his share be who stays by the baggage; they shall share alike.” 25So it has been from that day forward, that he made it a statute and an ordinance for Israel to this day.