Al-Kāfi - The Book of Fasting

Chapter: The Case of One Who Becomes a Muslim during the Month of Ramadan 3ـ أَبُو عَلِيٍّ الأَشْعَرِيُّ عَنْ ٠َّدِ بْنِ عَبْدِ الْجَبَّارِ عَنْ صَفْوَانَ بْنِ يَحْيَى عَنْ عِيصِ بْنِ الْقَاسِ٠ِ قَالَ سَأَلْتُ أَبَا عَبْدِ الله (عَلَيْهِ السَّلاَ٠ُوا فِي شَهْرِ رَ٠ُ الَّذِي أَسْلَ٠ُوا فِيهِ فَقَالَ لَيْسَ عَلَيْهِ٠ْ قَضَاءٌ وَلا يَوْ٠ُ الَّذِي أَسْلَ٠ُوا فِيهِ إِلاَّ أَنْ يَكُونُوا أَسْلَ٠ُوا قَبْلَ طُلُوعِ الْفَجْرِ.

He (the Imam) said, ‘They are not obligated for anything, not even the day in which they accept Islam except if they accept Islam before dawn.’” صحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (6/324))