Musnad Ahmad 30:3303

Ibn Numayr narrated to us, al-A‘mash narrated to us, from Abu Salih, from Abu Hurayrah, from the Prophet, peace and blessings of Allah be upon him, who said: "He forbade *al-wisal* (fasting continuously for days without breaking the fast)." They said: "Indeed, you practice *al-wisal*." He said: "I am not like you. I remain with my Lord; He feeds me and gives me drink. Take upon yourselves of deeds that which you are able to bear."