1 Samuel 30:23-25

23But David said, “No! You shouldn’t do this, my brothers. Look at what the Lord has given us! He has protected us and has delivered into our hands the raiding party that came against us.

24Who will listen to you in this matter? The portion of the one who went down into the battle will be the same as the portion of the one who remained with the equipment! Let their portions be the same!”

25From that time onward it was a binding ordinance for Israel, right up to the present time.