Tafsir Al-Jalalayn: An-Noor, Ayah 31

And tell believing women to lower their gaze away from what is not lawful for them to look at and to guard their private parts from what is not lawful for them to do with them and not to display their adornment except for what is apparent namely the face and the hands which may be seen by a stranger when there is no danger of either or both falling into temptation — this being one of two opinions. The second of these is that even this is forbidden because there is a presumption that these parts will cause temptation — and this is the preferred opinion if one must settle this topic with a definitive opinion; and let them draw their veils over their bosoms that is let them cover up their heads necks and chests with veils and not reveal their hidden adornment namely all that is other than the face and the hands except to their husbands bu‘ūl is the plural form of ba‘l ‘male spouse’ or their fathers or their husbands’ fathers or their sons or their husbands’ sons or their brothers or their brothers’ sons or their sisters’ sons or their women or what their right hands own all of whom are permitted to look thereat except for the part from the navel down to the knees which is unlawful for any other than their husbands to see; ‘their women’ however excludes disbelieving women for it is not permitted for Muslim women to reveal themselves to these; ‘what their right hands own’ comprises slaves; or such men who are dependant on what food may be left over not ghayri read as an adjective or read ghayra as an exceptive possessing any sexual desire not those men who are in sexual need of women so for example those whose male member cannot become erect; or children who are not yet aware of women’s private parts in the context of sexual intercourse and so to these they may reveal themselves except for that part from the navel to the knees. And do not let them thump with their feet to make known their hidden ornaments as in a rattling anklet and the like. And rally to God in repentance O believers repenting of the occasions on which you may have looked at what is forbidden to look at of such parts and otherwise so that you might be prosperous so that you might be saved from such sinful acts when your repentance thereof is accepted — in this verse the prevalent address is to males over females.