When Saul was instructed to attack the Amalekites, the Lord made it clear that there was to be no plunder (1 Samuel 15:1–3). It is not clear why David was allowed to keep the plunder. Perhaps it was due to the fact that he was on a rescue and recovery mission whereas Saul was instructed to exercise a scorched-earth policy.1
20 Et David prit tout le menu et le gros bétail; et ceux qui conduisaient ce troupeau et marchaient à sa tête disaient: C'est ici le butin de David.