1—Hair and the like are pure.
2—Meat, and whatever lies beneath the skin, is impure; tanning does not purify it.
3—The skin, which is an intervening layer between the two, has a ruling intermediate between the preceding two categories.
Supplement: The jurists—may Allah have mercy on them—stated that using the intestines and rumen as bowstrings—that is, as cords—constitutes tanning, meaning that it takes the place of tanning. (1) Accordingly, they do not become pure, though, according to the madhhab, they may be used with dry substances.
However, the author of al-Furūʿ—may Allah have mercy on him—one of the most prominent students of Shaykh al-Islam, especially in jurisprudence, says: “It may be held that it does not.” (2) That is, he considers the stronger view—whether according to the madhhab or according to the view he regarded as preponderant—to be that this does not constitute tanning. What he said is sound, because the intestines and rumen are part of the carcass itself. The correct view is that adopted by the author of al-Furūʿ.
On this occasion, it should be noted that when the phrase “it may be held that such-and-such” is used, this is among the expressions of the author of al-Furūʿ. When the phrase “it appears that such-and-such” is used, it is among the expressions of Marʿī, the author of al-Ghāyah. He was one of the later scholars and, in al-Ghāyah, combined al-Muntahā and al-Iqnāʿ.
Yet there is a vast difference between the reasoned determinations of the author of al-Furūʿ and the assessments of the author of al-Ghāyah in terms of strength, reasoning, and evidence. The determinations of the author of al-Furūʿ are generally founded upon legal principles and foundational rules, whereas the assessments of the author of al-Ghāyah are of a lower rank.