Is it permissible to use pig bristles for stitching?
Chapter on Utensils
Al-Mughni
Book of Purification
Primary text
There is a difference of opinion regarding the ruling on using pig bristles for stitching (*kharz*). One narration from Ahmad, attributed also to Ibn Sirin, Al-Hakam, Hammad, Ishaq, and Al-Shafi'i, states that it is disliked (*karaha*). The reasoning is that this constitutes the utilization of a najis (impure) substance, which is susceptible to becoming impure itself, thus prohibiting its benefit, similar to its hide.
Supporting text
The second narration permits stitching with pig bristles. Furthermore, stitching with vegetable fiber (*layf*) is preferred. Al-Hasan, Malik, Al-Awza'i, and Abu Hanifa permitted it, citing necessity. If stitching is performed while the object or the bristle itself is wet, the stitch becomes najis and is only purified by washing.