١٠- مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ مُحَمَّدِ بْنِ عِيسَى عَنْ أَبِي الْقَاسِمِ الصَّيْقَلِ قَالَ كَتَبْتُ إِلَيْهِ قَوَائِمُ السُّيُوفِ الَّتِي تُسَمَّى السَّفَنَ أَتَّخِذُهَا مِنْ جُلُودِ السَّمَكِ فَهَلْ يَجُوزُ الْعَمَلُ لَهَا وَلَسْنَا نَأْكُلُ لُحُومَهَا فَكَتَبَ (عَلَيْهِ السَّلام) لا بَأْسَ. 
10. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from Muhammad ibn Ahmad ibn ‘Isa from abu al-Qasim al-Sayqal who has said the following: “I once wrote to him (the Imam) , and asked, ‘There is a certain sheathing of swords called al-Safan (sandpaper) which is from skin of fish; if it is permissible to work with and we do not eat its meat.’ He (the Imam) wrote back, ‘It is not unlawful.’” 