It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that my beloved friend Abul Qasim (peace and blessings be upon him) advised me regarding three things which I will not leave until my death: (1) to perform ghusl (ritual bath) on the day of Jumu'ah (Friday), (2) to fast three days in every month, (3) to perform Witr prayer before sleeping.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 10273