Al-Kāfi - Volume 5 > Selling Arms to al- Sultan
Hadith #2

2- أَحْمَدُ بْنُ مُحَمَّدٍ عَنِ ابْنِ مَحْبُوبٍ عَنْ عَلِيِّ بْنِ الْحَسَنِ بْنِ رِبَاطٍ عَنْ أَبِي سَارَةَ عَنْ هِنْدٍ السَّرَّاجِ قَالَ قُلْتُ لأبِي جَعْفَرٍ (عَلَيْهِ السَّلام) أَصْلَحَكَ اللهُ إِنِّي كُنْتُ أَحْمِلُ السِّلاحَ إِلَى أَهْلِ الشَّامِ فَأَبِيعُهُ مِنْهُمْ فَلَمَّا أَنْ عَرَّفَنِيَ اللهُ هَذَا الأمْرَ ضِقْتُ بِذَلِكَ وَقُلْتُ لا أَحْمِلُ إِلَى أَعْدَاءِ اللهِ فَقَالَ احْمِلْ إِلَيْهِمْ فَإِنَّ اللهَ يَدْفَعُ بِهِمْ عَدُوَّنَا وَعَدُوَّكُمْ يَعْنِي الرُّومَ وَبِعْهُمْ فَإِذَا كَانَتِ الْحَرْبُ بَيْنَنَا فَلا تَحْمِلُوا فَمَنْ حَمَلَ إِلَى عَدُوِّنَا سِلاحاً يَسْتَعِينُونَ بِهِ عَلَيْنَا فَهُوَ مُشْرِكٌ.

2. Ahmad ibn Muhammad has narrated from ibn Mahbub from Ali ibn al-Hassan ibn Ribat from abu Sarah from Hind ibn Faddal-Sarraj who has said the following: “I once asked abu Ja’far, ‘Alayhi al-Salam, saying, ‘I pray to Allah to keep you well, I used to carry arms to sell to people of al-Sham. Ever since Allah has helped me to recognize the matter (Divine Authority of ‘A’immah) it bothers me, and I think I must not deliver arms to the enemies of Allah.’ He (the Imam) said, ‘You can do so because Allah repels through them our enemy and your enemy- the Romans - and sell it to them. When there is war among us, then do not carry arms to them. Those who carry arms to our enemies which help them against us, such people are like pagans.’”