Congregational Prayer and Its Virtue
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 57
وَقَالَ إِسْمَاعِيلُ اَلْجُعْفِيُّ لِأَبِي جَعْفَرٍ عَلَيْهِ اَلسَّلاَمُ: رَجُلٌ يُحِبُّ أَمِيرَ اَلْمُؤْمِنِينَ عَلَيْهِ اَلسَّلاَمُ وَ لاَ يَتَبَرَّأُ مِنْ عَدُوِّهِ وَ يَقُولُ هُوَ أَحَبُّ إِلَيَّ مِمَّنْ خَالَفَهُ قَالَ «هَذَا مِخْلَطٌ وَ هُوَ عَدُوٌّ فَلاَ تُصَلِّ وَرَاءَهُ وَ لاَ كَرَامَةَ إِلاَّ أَنْ تَتَّقِيَهُ.
Isma'il al-Ju'fi said to Abu Ja'far: "A man loves The Commander of the Faithful Imam Ali ibn Abi Talib عليه السلام but does not dissociate from his enemies, and he says, 'He (Ali) is dearer to me than those who opposed him.'" He (Abu Ja'far) replied: "This person is of mixed (belief) and is an enemy; do not pray behind him, nor is there any respect (to be shown to him) except if you must do so out of precaution."
- Ṣaḥīḥ al-Faqīh