Sayyiduna Tha'labah bin al-Hakam (may Allah be pleased with him) narrates: We got some of the enemy's sheep and goats, so we plundered them and set up our cooking pots. The Prophet (peace and blessings be upon him) passed by the pots; he (peace and blessings be upon him) gave the order and they were overturned. Then he said: "Plunder is not lawful."
Hadith Referenceالمعجم الكبير للطبراني / باب الثاء / 1365