Does the prayer become invalid if only a small portion of the 'awrah (intimate parts) is uncovered?

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The prayer is not invalidated if a minor portion of the 'awrah becomes uncovered. Ahmad and Abu Hanifa adhere to this view. The evidence is the narration by Abu Dawud, Al-Nasa'i, and others, wherein 'Amr ibn Salama al-Jurmi stated that while leading prayer wearing a small patched garment, his backside would become uncovered upon prostration. A woman commanded that the 'awrah of their reciter be covered, and he subsequently received a shirt. This incident was widespread and was not negated by the Prophet, peace be upon him, nor any of his companions. Furthermore, what is permissible in case of necessity (like uncovering a large area) should not invalidate prayer when only a small area is uncovered when there is no necessity. Also, avoiding minor unveilings is difficult, so it is pardoned, similar to minor amounts of blood.