It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that my beloved friend (peace be upon him) advised me regarding three things, which I will not abandon until my death: (1) to perform Witr prayer before sleeping, (2) to fast three days in every month, (3) to perform Ghusl (ritual bath) on Fridays.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 10111
Hadith Gradingحکم دارالسلام:حديث حسن، خ: 1178، م: 721، فيه انقطاع، الحسن لم يسمع من أبي هريرة