—the phrase “they neglected it” means that they postponed it beyond its appointed time. Whoever defers the prayer past its proper time is, in Allah’s own words, heedless of it and wasteful of it; he has been threatened with wayl (woe) and ghayy (ruin)—the latter is a valley in Hell. If a person forgets a prayer or sleeps through it, he must hasten to make it up. The Prophet said, “Whoever forgets a prayer or sleeps through it, let him perform it when he remembers it; there is no expiation for it other than that.”

One must therefore make up a missed prayer immediately: he is not to wait until the time of a similar prayer arrives, as some laypeople imagine, nor delay it until a period in which prayer is disliked has ended. Rather, he must offer it on the spot.

Second: Covering the ʿawrah (private parts)

Among the prerequisites of prayer is covering the ʿawrah—that which must be concealed, whose exposure is indecent and shameful. Allah, exalted is He, says, “O children of Adam, dress well for every place of worship” [Qur’an 7:31], meaning at every prayer. The Prophet said, “Allah does not accept the prayer of a menstruating woman,” that is, a woman who has reached puberty, “unless she wears a head-cover,” narrated by Abu Dawud and al-Tirmidhi, who graded it sound.

Ibn ʿAbd al-Barr said, “There is consensus that the prayer of someone who leaves his garment aside, while able to clothe himself, and prays naked is invalid. There is no dispute over the obligation of covering the ʿawrah in prayer and in the presence of people, and—on the stronger view—even when alone.” The Prophet said, “Guard your private parts except from your wife or those whom your right hand possesses.” I asked, “What if people are gathered together?” He replied, “If …”