The legal category through which haya becomes a rule is awra, the part of the body that is to be covered. The jurists derive its extent from the two verses on modest dress together with reports of practice, and they do not all reach the same answer. For men the schools broadly agree on the region from navel to knee, with differences at the edges. For women in the presence of unrelated men, the majority position covers the whole body with the face and hands excepted, and a minority position within and across schools includes the face. The extent also varies by context: what is covered before other women, before close relatives and in prayer are three separate questions with three separate answers.
The vocabulary in the verses is itself part of the argument. The khimar is a head covering already in use that women are told to draw across the chest, and the jilbab is an outer garment to be drawn close, and neither word settles by itself what a garment must look like. Regional custom filled the gap, which is why dress that is regarded as fulfilling the requirement looks entirely different in West Africa, the Gulf, South Asia and Southeast Asia.
Modern argument has been intense, inside the tradition as well as outside it, and anthropological work on contemporary piety movements has shown participants describing the practice as the cultivation of a disposition rather than as compliance with a rule. The atlas records the range and does not instruct.