Chapter on the Recommended Fasts of the Year
Man Lā Yaḥḍuruh al-Faqīh|Volume 2|Book 2|Chapter 4
وَ رَوَى جَمِيلُ بْنُ دَرَّاجٍ عَنْهُ عَلَيْهِ اَلسَّلاَمُ أَنَّهُ قَالَ: «مَنْ دَخَلَ عَلَى أَخِيهِ وَ هُوَ صَائِمٌ فَأَفْطَرَ عِنْدَهُ وَ لَمْ يُعْلِمْهُ بِصَوْمِهِ فَيَمُنَّ عَلَيْهِ كَتَبَ اَللَّهُ لَهُ صَوْمَ سَنَةٍ ».
It is narrated by Jamil ibn Darraj from Abu Abdullah عليه السلام that Imam عليه السلام said: "Whoever visits his brother while fasting, then breaks his fast at his house without informing him of his fasting to gain favor, Allah سبحانه وتعالى will write for him the reward of fasting a full year."
- Ṣaḥīḥ al-Faqīh, p. 90