Before whom should women cover the face?
A: The face should be covered before any marriageable relative, who is a nonMahram (not a spouse or unmarriageable relative) to a woman. This is according to the most correct opinion of scholars, whether this relative is a paternal or maternal cousin, one of the neighbors, or someone else, for Allah (Exalted be He) says addressing all Muslims during the lifetime of the Messenger of Allah (peace be upon him) and those who succeed them:
And when you ask (his wives) for anything you want, ask them from behind a screen: that is purer for your hearts and for their hearts.
O Prophet! Tell your wives and your daughters and the women of the believers to draw their cloaks (veils) all over their bodies (i.e. screen themselves completely except the eyes or one eye to see the way). That will be better, that they should be known (as free respectable women) so as not to be annoyed.
And tell the believing women to lower their gaze (from looking at forbidden things), and protect their private parts (from illegal sexual acts) and not to show off their adornment except only that which is apparent (like both eyes for necessity to see the way, or outer palms of hands or one eye or dress like veil, gloves, headcover, apron, etc.), and to draw their veils all over Juyûbihinna (i.e. their bodies, faces, necks and bosoms) and not to reveal their adornment except to their husbands, or their fathers, or their husband's fathers
When I heard the voice of Safwan ibn Mu`attal I put a khimar on my face, and he has seen me before Hijab
When a woman reaches the age of puberty, nothing should be seen of her but this and that; and he pointed to the face and hands