My friend (i.e. the Prophet) instructed me to observe three practices that I do not leave while traveling nor while resident, to pray two rakʿahs in the forenoon, to fast three days every month and not to sleep but after observing the witr.
أَوْصَانِي خَلِيلِي ﷺ بِثَلاَثٍ لاَ أَدَعُهُنَّ فِي سَفَرٍ وَلاَ حَضَرٍ رَكْعَتَىِ الضُّحَى وَصَوْمِ ثَلاَثَةِ أَيَّامٍ مِنَ الشَّهْرِ وَأَنْ لاَ أَنَامَ إِلاَّ عَلَى وِتْرٍ