Mutarrif bin Abdullah bin Shukhair narrated from his father (Sayyiduna Abdullah, may Allah be pleased with him) that a man was mentioned to the Messenger of Allah (peace and blessings be upon him) who always fasted. The Prophet (peace and blessings be upon him) said: "He neither fasted nor broke his fast."
That is, he neither receives the reward of fasting nor of breaking the fast, because he has acted contrary to the Shari‘ah. Allah Ta‘ala has not commanded anywhere that His servant should fast continuously without break. Therefore, for the person who fasts every single day, this warning is given, and the Prophet sallallahu alayhi wa sallam, as a form of reprimand and censure, said that he neither fasted nor broke the fast.
The best method of fasting is that one fasts one day and breaks the fast the next day. Apart from this, if one fasts on the white days (Ayyam al-Beedh) of every month, it is very virtuous. And following the Sunnah of the Messenger of Allah sallallahu alayhi wa sallam, fasting on Mondays and Thursdays in the week also holds great significance, as will be mentioned ahead.