and likewise its dual and plural are all termed junub. The designation is said to derive from the command that such a person must keep away from the place of prayer until he purifies himself; or because his seminal fluid separates from, and is distant from its original location; or, as some say, because he must stay apart from people until he performs the obligatory bath.
– “li-yaghtasil” (so that he may bathe): the prefixed lām is the lām of purpose—the same as the lām of “in order that.” The verb is in the subjunctive, governed by an implied “an,” and whatever precedes the lām is intended only as a means to bring about what follows it.
– “lā yajnub” (it does not become junub): derived from janaba with the pattern faʿila or faʿula—hence the middle root letter may be vocalised with kasra or ḍamma, and in the imperfect tense the nūn may accordingly be fathah or ḍamma. That is if the root is treated as trilateral; it may also be considered quadriliteral, from ajnaba – yujnib, meaning “to induce janāba.” In either case, the sense is that water itself cannot contract janāba.

Points derived from the ḥadith

1. It is permissible for a man to bathe with water left over by a woman, even if she was junub—and, a fortiori, for a woman to bathe with water left over by a man. Ibn ʿAbd al-Barr said in al-Istidhkār: “The default ruling for water is purity, for Allah created it purifying, and it remains so until the Muslims unanimously agree that it has become impure. The believer himself is not impure; impurity is only an accidental quality. In this regard a woman is exactly like a man, provided both are free of anything that would actually render the water impure.”
2. When a junub person performs ghusl, or someone performing wuḍūʾ draws water directly from a vessel, that does not affect the water’s capacity to purify; the water retains its original purifying status.
3. Al-Wazīr, al-Nawawī, and others report consensus that a man may make wuḍūʾ with water left over by a woman even if she had been alone with it—except in one of the two narrations from Imām Aḥmad. That is the narration most widely known among our Ḥanbalī colleagues: if a woman was alone with a small quantity of water and performed a complete purification from ritual impurity, that water will not afterwards purify a man.
   The other narration, cited in al-Insāf, states that according to Imām Aḥmad the water still removes a man’s minor impurity; this is the sounder of the two views and was preferred by Ibn ʿAqīl, Abū al-Khaṭṭāb, and al-Majd. Al-Sharḥ al-Kabīr comments: “That opinion is more consistent with analogy, and it is also the position of the other three Imams.”
   As for a woman making wuḍūʾ with water left over by a man, it is unanimously permitted.