Al-Kāfi - The Book of Fasting

Chapter: The Day That Is Doubtful About Its Being of the Month of Sha‘ban or the Month of Ramadan َّدٍ عَنِ ابْنِ أَبِي الصُّهْبَانِ عَنْ ٠َّدِ بْنِ بَكْرِ بْنِ جَنَاحٍ عَنْ عَلِيِّ بْنِ شَجَرَةَ عَنْ بَشِيرٍ النَّبَّالِ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ السَّلاَ٠) قَالَ سَأَلْتُهُ عَنْ صَوْ٠ِ الشَّكِّ فَقَالَ صُ٠ِنْ شَعْبَانَ كَانَ تَطَوُّعاً وَإِنْ يَكُ ٠ٌ وُفِّقْتَ لَهُ.

He (the Imam) said, ’Fast on such day, if it is of al-Sha £ ban, it is optional and if it is of the month of Ramadan then it is a day in which you have a fortunate chance.’” حسن - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (6/239))