Chapter on Khums
Man Lā Yaḥḍuruh al-Faqīh|Volume 2|Book 1|Chapter 7
وَ قَالَ اَلصَّادِقُ عَلَيْهِ اَلسَّلاَمُ: «إِنَّ اَللَّهَ لاَ إِلَهَ إِلاَّ هُوَ لَمَّا حَرَّمَ عَلَيْنَا اَلصَّدَقَةَ أَنْزَلَ لَنَا اَلْخُمُسَ فَالصَّدَقَةُ عَلَيْنَا حَرَامٌ وَ اَلْخُمُسُ لَنَا فَرِيضَةٌ وَ اَلْكَرَامَةُ لَنَا حَلاَلٌ.
Imam Jafar ibn Muhammad Al-Sadiq عليه السلام said: "Indeed, Allah سبحانه وتعالى, there is no god but Him, when He prohibited charity (Sadaqah) for us, He ordained Khums for us. Thus, charity is forbidden to us, Khums is an obligation for us, and gifts of honor are permissible for us."
- Ṣaḥīḥ al-Faqīh