Musnad Ahmad 30:2088

'Attab ibn Ziyad narrated to us, he said: 'Abdullah ibn al-Mubarak narrated to us, he said: 'Abdullah ibn Lahi'ah informed us, from Yazid ibn Abi Habib, he said: Lahi'ah ibn 'Uqbah narrated to me, from Abu al-Ward, from Abu Hurayrah, he said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Beware of the *munaffalah* (spoils-seeking) horses, for if they encounter [the enemy], they flee, and if they take spoils, they embezzle."