Thus, covering the ʿawrah is a prerequisite for the validity of the prayer whenever one is able to do so. As for the case mentioned in the question—namely, that part of the worshipper’s ʿawrah became exposed without his noticing it until he finished the prayer and the people present alerted him—there is some detail to consider:

• If what became exposed was a substantial portion, he must repeat the prayer.
• If only a small part was uncovered and he did not do so intentionally, then his prayer is sound, God willing. The proof is the report concerning ʿAmr ibn Salamah (may Allah be pleased with him). When he was still a young boy, he used to lead his people in prayer; whenever he prostrated, a part of his ʿawrah would be revealed, and the women standing behind the row could see it. Yet he was not ordered to repeat the prayer, and this occurred during the lifetime of the Prophet (peace and blessings be upon him). This shows that if a small portion of the ʿawrah becomes uncovered unintentionally, the prayer remains valid.

However, if a person uncovers his ʿawrah on purpose, his prayer is invalid even if the uncovered area is small. Likewise, if the uncovering is unintentional but involves a large portion, he must repeat the prayer because the condition has not been fulfilled.

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Praying while seated

Question: My father performs the prayer while seated because of pain in his knees that prevents him from standing. Is there any sin upon him? May you kindly advise us.

Answer: There is no doubt that standing in an obligatory prayer is one of its pillars; the prayer is not valid without it when one is able, for Allah the Exalted says, “And stand before Allah devoutly obedient” (al-Baqarah 2:238), and the Prophet (peace and blessings be upon him) said, “Pray standing; if you cannot, then pray sitting.” Therefore, it is obligatory for the worshipper in an obligatory prayer to perform it standing. If, however, he is unable to do so because of illness, then