1 Samuel 30:23-25

23“You must not do so, my brothers with what Adonai has given us,” David said. “It is He who has protected us and gave into our hands the raiding band that attacked us.

24Who would listen to you in this matter? The share of him who went down to the battle is to be the same as that of him who remained by the baggage. They will share alike.”

25So it has been from that day forward—he made it a statute and an ordinance for Israel to this day.