 وَ بِهَذَا الْإِسْنَادِ عَنِ الْحُسَیْنِ بْنِ سَعِیدٍ عَنْ مُحَمَّدِ بْنِ یَحْیَی أَخِی مُغَلِّسٍ الصَّیْرَفِیِّ عَنْ حَمَّادِ بْنِ عُثْمَانَ قَالَ سَمِعْتُ أَبَا عَبْدِ اللَّهِ ع یَقُولُ صَامَ رَسُولُ اللَّهِ ص حَتَّی قِیلَ مَا یُفْطِرُ وَ أَفْطَرَ حَتَّی قِیلَ مَا یَصُومُ ثُمَّ صَامَ صَوْمَ دَاوُدَ ع یَوْماً وَ یَوْماً ثُمَّ قُبِضَ ص عَلَی صَوْمِ ثَلَاثَهِ أَیَّامٍ فِی الشَّهْرِ وَ قَالَ یَعْدِلْنَ الدَّهْرَ وَ یَذْهَبْنَ بِوَحَرِ الصَّدْرِ قَالَ قُلْتُ جُعِلْتُ فِدَاکَ وَ أَیُّ أَیَّامٍ هِیَ فَقَالَ أَوَّلُ خَمِیسٍ فِی الشَّهْرِ وَ أَوَّلُ أَرْبِعَاءَ بَعْدَ الْعَشْرِ مِنْهُ وَ آخِرُ خَمِیسٍ مِنْهُ قَالَ قُلْتُ وَ لِمَ صَارَتْ هَذِهِ الْأَیَّامُ قَالَ لِأَنَّ مَنْ کَانَ قَبْلَنَا مِنَ الْأُمَمِ إِذَا أُنْزِلَ عَلَیْهِمُ الْعَذَابُ نَزَلَ فِی هَذِهِ الْأَیَّامِ فَصَامَ رَسُولُ اللَّهِ ص هَذِهِ الْأَیَّامَ کُلَّهَا لِأَنَّهَا الْأَیَّامُ الْمَخُوفَهُ.
6.  It  is  narrated  by  Imam  Ja’far  Sadiq    that  the  Holy Prophet (s.a.w.s.) used to fast so much that people used to say  that  he  does  not  miss  any  fast.  Then  he  used  to discontinue  observing  fast  for  so  many  days  that  people used to say that he does not observe fast. Then he started observing fast for alternate days like Dawood . When he passed away from this world, he was fasting (one of the three fasts of a month). He said that these fasts are equal to the fasts of an age and it kills the evil thoughts arising in one’s  heart.”  The  narrator  asked,  “May  I  be  sacrificed  on you,  what  are  those  days?”  Imam    replied,  “First Thursday of every month, the Wednesday coming after first ten days of a month and last Thursday of the month?” The narrator asked, “Why are these days selected?” Imam  replied,  “The  communities  before  us  had  to  bear  the chastisement  on  these  days.  Hence  the  Holy  Prophet (s.a.w.s.) used to fast during these days and they are the days of fearing Allah.”