The reasons for their divergence on this question trace back to three considerations:

1. Their different readings of the Almighty’s words, “And purify your garments” (al-Muddaththir 74:4): should the verse be understood in its literal sense or as a metaphor?

2. The apparent conflict of ḥadith texts regarding whether removal of impurity is compulsory.

3. Their disagreement over commands and prohibitions that are tied to an intelligible rationale: Does the discernible rationale serve as a contextual clue that shifts a command from obligation to recommendation and a prohibition from strict unlawfulness to mere reprehensibility, or does it not? And is there any distinction in this respect between acts of worship whose rationale is perceptible and those whose rationale is not?

Those who drew a distinction did so because most Sharīʿah rulings whose rationale is intelligible pertain either to virtuous character traits or to worldly benefits, matters that are usually recommended rather than obligatory. Hence, whoever understood the verse “And purify your garments” as referring to tangible clothing concluded that cleansing from impurity is obligatory; whereas whoever took it as a figurative allusion to purifying the heart found in it no proof of obligation.

As for the seemingly contradictory reports, they include the famous ḥadith of the two men in their graves and the Prophet’s—peace and blessings be upon him—statement concerning them: “They are being punished, yet they are not being punished for something grave; one of them used not to keep himself clear of his urine.” The outward sense of this ḥadith points to obligation, for punishment is linked only to neglect of a duty. Set against it is the authentic report that while he—peace and blessings be upon him—was praying, the placenta of a camel, smeared with blood and filth, was thrown on him and he nevertheless continued the prayer. Its apparent meaning is that, had removing impurity been obligatory like ablution from minor impurity, he would have broken the prayer.

Another report relates that the Prophet—peace and blessings be upon him—was praying one of the prescribed prayers wearing his sandals. He removed them, whereupon the people removed theirs. He objected to their doing so and said, “I only removed them because Gabriel informed me that there was filth on them.” The plain sense of this is that, had removal of impurity been obligatory, he would not have continued the prayer already performed.

Accordingly, whoever gives precedence to the outward indications of the texts will pronounce it either obligatory—if he favors the ḥadith whose surface meaning indicates obligation—or recommended—if he favors the ḥadith whose surface meaning indicates recommendation, namely, the two reports that suggest removal of impurity is an emphatic Sunnah. Those who opt for harmonizing the texts differ: some say it is obligatory when one remembers and is able, waived when one forgets or lacks the ability; others maintain that it is obligatory in an absolute sense but not a condition for the validity of the prayer, and this is an opinion