"The Messenger of Allah enjoyed three things upon me: To sleep after praying Witr, to perform Ghusal on Friday, and to fast three days of each month." (Sahih). (Using translation from Nasāʾī 2405)
أَوْصَانِي خَلِيلِي رَسُولُ اللهِ ﷺ بِثَلَاثٍ الْوَتْرِ قَبْلَ النَّوْمِ وَصِيَامِ ثَلَاثَةِ أَيَّامٍ مِنْ كُلِّ شَهْرٍ وَالْغُسْلِ يَوْمَ الْجُمُعَةِ