Musnad Ahmad 32:308

Ibn Abi ‘Adi narrated to us, from Humayd, from Thabit, from Anas, who said: The Prophet, peace and blessings of Allah be upon him, fasted continuously at the end of the month, and some of the people also fasted continuously. This reached the Prophet, peace and blessings of Allah be upon him, so he said: "If the month had been extended for us, I would have fasted continuously in a way that would have made those who go to extremes abandon their extremism. I am not like you; I spend the night while my Lord feeds me and gives me drink."