Surah an-Nur verse 31 reads

And say to the faithful women to lower their gazes, and to guard their private parts, and not to display their beauty except what is apparent of it, and to extend their headcoverings (khimars) to cover their bosoms, and not to display their beauty except to their husbands, or their fathers, or their husband's fathers, or their sons, or their husband's sons, or their brothers, or their brothers' sons, or their sisters' sons, or their womenfolk, or what their right hands rule (slaves), or the followers from the men who do not feel sexual desire, or the small children to whom the nakedness of women is not apparent, and not to strike their feet (on the ground) so as to make known what they hide of their adornments. And turn in repentance to God together, O you the faithful, in order that you are successful.