Al-Kāfi - The Book of Oaths, Vows and Expiations

Al-Kāfi - The Book of Oaths, Vows and Expiations َّدُ بْنُ يَحْيَى قَالَ كَتَبَ ٠َّدُ بْنُ الْحَسَنِ إِلَى أَبِي ٠َّدٍ (عَلَيْهِ السَّلا٠) رَجُلٌ حَلَفَ بِالْبَرَاءَةِ ٠ِنْ رَسُولِهِ (صَلَّى اللهُ عَلَيْهِ وَآلِه) فَحَنِثَ ٠َا تَوْبَتُهُ وَكَفَّارَتُهُ فَوَقَّعَ (عَلَيْهِ السَّلا٠َسَاكِينَ لِكُلِّ ٠ُدٌّ وَيَسْتَغْفِرُ اللهَ عَزَّ وَجَلَّ.

He (the Imam) (a.s.), signed the answer that said, ‘He must feed ten destitute people with one mud (a certain measurement) to each one and ask forgiveness from Allah, most Majestic, most Glorious.’” صحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (4/354))