Sahih Muslim
The Book of Fasting (Kitab Al-Sawm)
Book Number: 006 / Hadith Number: 2427
Ibn 'Umar reported that the Messenger of Allah (may peace be upon him) abserved fasts uninterruptedly in Ramadan and the people (in his wake) did this. But he forbade them to do so. It was said to him (to the Holy Prophet): You yourself observe the fasts uninterruptedly (but you forbid us to do so) Upon this he said: I am not like you; I am fed and supplied drink (by Allah).