Musnad Ahmad 32:1145

Yazid narrated to us, Shu'bah informed us, from Qatadah, from Anas, from the Prophet, peace and blessings of Allah be upon him, who said: "Do not practice *wisal* (continuous fasting without breaking it at night)." They said: "O Messenger of Allah, you practice *wisal*." He said: "I am not like one of you; I spend the night while I am fed and given to drink."