Musannaf Ibn Abi Shayba 38:94

Mu'awiyah ibn Hisham narrated to us, he said: Ibn Abi Dhi'b narrated to us, from the one who narrated it to him, from Ali, he said: When Mu'awiyah fought, he reached the water before him. He (Ali) said: "Leave them, for water is not withheld."