عَنْ عَبْدِ الْمَلِكِ بْنِ الْمِنْهَالِ عَنْ أَبِيهِ رَضِيَ اللَّهُ عَنْهُ قَالَ: أَمَرَنَا رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ بِأَيَّامِ الْبِيضِ فَهُوَ صَوْمُ الشَّهْرِ
It is narrated from Sayyiduna Minhal (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him and his family) commanded us to fast on the White Days; these are equal to fasting for a whole month.