100 years of fasts

 Sayyidunā Salmân Fârsi rađiyAllāhu ánhu narrates that the Holy Prophet şallAllāhu álayhi wa sallam said, 

There is a day and a night in the month of Rajab on which if a person fasts during the day and stands (for worship) in the night, it will be as if he fasted for one hundred years. This is the 27th of Rajab. This is the day on which the beloved of Allâh şallAllāhu álayhi wa sallam was given Prophet hood.[1] 

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[1] Imâm al-Bayhaqī’s, Shua’b al-Imân, vol. 3, pp. 374, Hadīth 3811