Thawāb al-Aʿmāl wa ʿiqāb al-Aʿmāl
Hadith 258 أَبِی ره قَالَ حَدَّثَنِی أَحْمَدُ بْنُ إِدْرِیسَ قَالَ حَدَّثَنِی مُحَمَّدُ بْنُ أَحْمَدَ قَالَ حَدَّثَنَا مُوسَی بْنُ عُمَیْرٍ عَنْ عَلِیِّ بْنِ الْحَکَمِ عَنْ أَحْمَدَ بْنِ زَیْدٍ عَنْ مُوسَی بْنِ جَعْفَرٍ ع قَالَ: مَنْ صَامَ أَوَّلَ یَوْمٍ مِنَ الْعَشْرِ عَشْرِ ذِی الْحِجَّهِ کَتَبَ اللَّهُ لَهُ صَوْمَ ثَمَانِینَ شَهْراً فَإِنْ صَامَ التِّسْعَ کَتَبَ اللَّهُ لَهُ صَوْمَ الدَّهْرِ.
2. My father (rah) said: it was narrated to me by Ahmad b. Idris who said it was narrated to me by Muhammad b. Ahmad who said it was narrated to us by Musa b. ’Umayr from Ali b. al-Hakam from Ahmad b. Zayd from Musa b. Ja’far (a.s.) who said: “One who fasts on the first day of Zilhajj Almighty Allah would note down the reward of the fasts of eighty months for him. If he observes fast for nine days Allah would note the reward of fasts of an age for him.”