Musnad Ahmad 1034:201

Yazid narrated to us, Sharik ibn Abdullah informed us, from Asim ibn Abi al-Najud, from Zirr ibn Hubaysh, who said: I said—meaning to Hudhayfah—: "O Abu Abdullah, did you eat the pre-dawn meal (suhur) with the Messenger of Allah, peace and blessings of Allah be upon him?" He said: "Yes." I said: "Could a man see the landing spots of his arrows?" He said: "Yes, it was daytime, except that the sun had not yet risen."