Musnad Ahmad 31:556

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from Abu 'Amr al-Nadbi, who said: I heard Abu Sa'id al-Khudri saying: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Do not practice continuous fasting (wisal)." They said: "But you practice continuous fasting, O Messenger of Allah." He said: "I am not like you; I spend the night while I am fed and given to drink."