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 leave until my death): (1) To perform the Witr prayer before sleeping, (2) To fast three days in every month, (3) Never to abandon two rak'ahs of the Duha (forenoon) prayer.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 10450
Hadith Gradingحکم دارالسلام:حديث صحيح، خ: 1178، م: 721، وهذا إسناد ضعيف لضعف ليث، وشهر، وإن كان ضعيفا، قد توبع