Musannaf Ibn Abi Shayba 36:206

Abu Mu'awiyah narrated to us, from al-A'mash, from Abu Salih, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The spoils of war were not made lawful for a people with black heads before you. A fire used to descend from the sky and consume them. Then, when the day of Badr arrived, the people hastened toward the spoils of war. So Allah revealed: 'Had it not been for a decree from Allah that preceded, you would have been touched by a great punishment for what you took. So eat of what you have taken as spoils of war, lawful and good.'"