Is it true that it was narrated from Ali and Ibn Mas’ud – may Allah be pleased with them both – that they held the view of the purity of the hide of an animal whose meat is permissible to eat, through tanning?

The authoritative fatwa (legal opinion) states that all hides of dead animals become pure through tanning, whether the animal's meat is permissible to eat or not.

As for what is attributed to Ali and Ibn Mas'ud (may Allah be pleased with them), it includes all hides of dead animals except for dogs and pigs.

Imam An-Nawawi clarified that the madhhab (school of thought) of the Shafi'is and others is the purity of all hides of dead animals, except for dogs, pigs, and what is born from them.

Moreover, the hadith of Abdullah ibn Ukaym: "Do not benefit from the hide nor the sinew of a dead animal" contains weakness and is disturbed (mudtarib); it is also mursal (a hadith narrated by a Tabi'i directly from the Prophet without mentioning a Companion). It is contradicted by other more authentic and widely narrated hadiths. A reconciliation between them is possible by interpreting the prohibition as being specific to the state before tanning.