The Hanbali jurists—along with others—have held that every prohibited creature, land or bird, whose size equals or is smaller than that of a cat falls under the same ruling as the cat with respect to ritual purity and the permissibility of touching or handling it. The point here is the purity of their bodies and whatever they come into contact with; it does not make their flesh lawful to eat after slaughter. The stronger view, however, restricts this ruling to those forbidden animals that people commonly encounter and cannot realistically avoid, whether large or small, because that is the operative cause indicated by the Prophet’s words, “They are among those who move about among you.”

His statement, “It is not impure,” establishes the purity of every part of the cat’s body. This is more correct than the opinion that limits its purity to its drinking residue and whatever its mouth touches while deeming the rest of its body impure. Such a restriction contradicts the obvious sense of the hadith and its stated reason, namely, “among those who move about among you,” for one who circulates freely among people naturally contacts things with his entire body.

Ibn ʿAbd al-Barr said: The hadith proves that anything we are permitted to keep as a companion has pure leftover water, because it is among those who move about among us. The phrase “those who move about among us” refers to creatures that enter our quarters and mix with us.

By implication, the hadith teaches the desirability of avoiding impure substances, and that when need or necessity requires touching them one must still seek to remain clean of them—for instance, using the left hand for cleansing after relieving oneself or for removing filth and impurities.