Chapter on Khums
Man Lā Yaḥḍuruh al-Faqīh|Volume 2|Book 1|Chapter 7
وَ رَوَى أَحْمَدُ بْنُ مُحَمَّدِ بْنِ أَبِي نَصْرٍ عَنْ أَبِي اَلْحَسَنِ اَلرِّضَا عَلَيْهِ اَلسَّلاَمُ قَالَ: سَأَلْتُهُ عَمَّا يَجِبُ فِيهِ اَلْخُمُسُ مِنَ اَلْكَنْزِ فَقَالَ «مَا تَجِبُ اَلزَّكَاةُ فِي مِثْلِهِ فَفِيهِ اَلْخُمُسُ ».
Ahmad ibn Muhammad ibn Abi Nasr narrated from Abu al-Hasan Imam Ali ibn Musa Ar-Ridha عليه السلام: I asked him about what amount of a buried treasure (kanz) makes Khums obligatory. Imam عليه السلام replied: "Whatever amount requires Zakat in its equivalent also requires Khums."
- Ṣaḥīḥ al-Faqīh