Hadith 2130
Sayyida Mu’adhah (may Allah be pleased with her) narrates that I asked Sayyida Aisha (may Allah be pleased with her), “Did the Messenger of Allah (peace and blessings be upon him) fast every month, or did he fast three days in every month?” She replied, “Yes.” She (Mu’adhah) asked, “On which days did he fast?” Sayyida Aisha (may Allah be pleased with her) said, “He did not mind on which days he fasted.”