Sunan Ibn Majah
Sunan Ibn Majah 1708
حَدَّثَنَا سَهْلُ بْنُ أَبِي سَهْلٍ، حَدَّثَنَا أَبُو مُعَاوِيَةَ، عَنْ عَاصِمٍ الأَحْوَلِ، عَنْ أَبِي عُثْمَانَ، عَنْ أَبِي ذَرٍّ، قَالَ: قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " مَنْ صَامَ ثَلاَثَةَ أَيَّامٍ مِنْ كُلِّ شَهْرٍ فَذَلِكَ صَوْمُ الدَّهْرِ " . فَأَنْزَلَ اللَّهُ عَزَّ وَجَلَّ تَصْدِيقَ ذَلِكَ فِي كِتَابِهِ {مَنْ جَاءَ بِالْحَسَنَةِ فَلَهُ عَشْرُ أَمْثَالِهَا} فَالْيَوْمُ بِعَشْرَةِ أَيَّامٍ .
Unreviewed translation. All hadiths in this collection are available in five languages. Titles and introductions may remain in Arabic.
Sahl ibn Abi Sahl narrated to us; Abu Muawiyah narrated to us, from Asim al-Ahwal, from Abu Uthman, from Abu Dharr, who said: The Messenger of Allah (peace and blessings be upon him) said: ‘Whoever fasts three days of every month, that is the fast of a lifetime.’ Allah, Mighty and Majestic, sent down confirmation of that in His Book: ‘Whoever comes with a good deed will have ten like it.’ A day is counted as ten days.
Notes and open questions — unreviewed
The Qur’anic wording is translated from the Arabic quoted in this source, and the following explanation about a day counting as ten days is retained.