It was narrated from ‘Abdul-Malik bin Minhal, from his father that: The Messenger of Allah ( صلی اللہ علیہ وسلم ) used to enjoin fasting the bright days – the thirteenth, fourteenth and fifteenth (when the moon is full). He said:“It is like fasting for a lifetime.”Another chain from 'Abdul-Malik bin Qatadah bin Malhan Al-Qaisi, from his father, from the Prophet ( صلی اللہ علیہ وسلم ) with similar wording. Ibn Majah said: Shu'bah erred (in the name of one of the narrators)and Hammam was correct.

It was narrated from Abu Dharr that the Messenger of Allah ( صلی اللہ علیہ وسلم ) said:`“Whoever fasts three days in every month, that is fasting for a lifetime.”Then, in testimony of that, Allah revealed:“Whoever brings a good deed shall have ten time the like thereof to his credit.” [6:160] So one day is equivalent to ten (in reward).

It was narrated from Mu’adhah Al-‘Adawiyyah that ‘Aishah said:`“The Messenger of Allah ( صلی اللہ علیہ وسلم ) used to fast three days of each month.”I said:“Which were they?”She said:“He did not care which days they were.”