Abu Dawud
Fasting
Book Number: 007 / Hadith Number: 2409
Narated By AbuBakrah : The Prophet (pbuh) said: One of you should not say: I fasted the whole of Ramadan, and I prayed during the night in the whole of Ramadan. I do not know whether he disliked the purification; or he (the narrator) said: He must have slept a little and taken rest.