Musnad Ahmad 30:2140

'Affan narrated to us, he said: 'Abd al-Wahid narrated to us, he said: Ma'mar narrated to us, from al-Zuhri, from Abu Salamah, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "A person with sick camels should not bring them to water alongside a person with healthy camels."