The Prophet—peace and blessings be upon him—prohibited slaughtering with a claw, explaining that it is the blade of the Abyssinians,(1) just as he explained that a tooth is a bone.
The jurists then differed. The scholars of opinion held that the reason for the prohibition is that slaughtering with a tooth or claw resembles strangulation, or at least leads to it, and an animal that dies by strangulation is unlawful. On that basis they permitted slaughtering with a detached tooth or claw, because slaughter carried out with a separate, sharp instrument(2) involves no strangulation.
The majority, however, forbade it outright, for the Prophet—peace and blessings be upon him—excluded the tooth and the claw from the instruments that make the blood flow,(3) which shows that they are among the sharp implements with which slaughter is not valid. Had the reason been strangulation, he would not have excluded them. A mere likelihood is only treated as certainty when the underlying wisdom is hidden or indeterminate; when it is clear and well defined, it is not.
Moreover, this view contradicts the explicit rationale given by the Messenger of Allah—peace and blessings be upon him—in the ḥadīth.
These scholars then disagreed whether slaughtering with the rest of the bones is likewise forbidden, by applying the general rationale; within the school of Aḥmad and others there are two opinions.
According to all three positions,(5) his—peace and blessings be upon him—statement, “As for the claw, it is the knife of the Abyssinians,” after