Zuhayr bin Harb زهير بن حرب بن شداد أبو خثيمة · Fasting (Kitab Al-Siyam)

The Prophet (ﷺ) 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.

The apostle of Allah (ﷺ) used to fast three days every month: Monday, Thursday and Monday in the next week.