Prohibition of Fasting Continuously
Aishah (radi Allahu anha) reported that the Prophet (sal Allahu alaihi wa sallam) prohibited his companions out of mercy for them, from observing continuous fasting without a break. They said: “But you observe fast continuously”. He replied, “I am not like you. I spend the night while my Rubb provides me with food and drink.”
[Sahih al-Bukhari and Muslim]
(This means that Allah has bestowed upon him the power of endurance like that of a person who eats and drinks)
The words “I am not like you” should not be taken to mean here: “I am not a human like you”. What they really mean is that no one else has that special contact with Allah which he has. On account of this quality which was special to the Prophet (sal Allahu alaihi wa sallam), it is prohibited to keep fast continuously. In fact it is not only prohibited, but unlawful. In such cases, it is obligatory for Muslims to follow him faithfully.
And Allah Knows Best!