Regarding the statement of Allaah: “And to draw their khimaars (veils) over their juyoob (bosoms)” [24:31], Ibn ‘Uthaymeen mentions:
“The khimaar is that which a woman uses to cover and veil her head, such as a head cloth. So if she was commanded to place the khimaar over her jayb (bosom), then she was also commanded with covering her face, whether it is because wearing the khimaar necessitates that or because it is understood from general reasoning.
This is since if covering the neck and bosom are obligatory, then veiling the face is an obligation for all the more reason, since it is the source of beauty and enticement.
Indeed, when people seek the beauty of a figure, they do not ask except concerning the face. If it is beautiful, they do not look towards anything else in the same manner as possessing importance. This is why when it is said that such and such woman is beautiful, one doesn’t understand from these words anything except the beauty of the face.(1)
So it is clear that the face is the place of beauty that is asked about and informed of. And if it is this way, then how can we come to understand that this religion, which is based upon wisdom, would obligate the covering of the neck and chest and then allow the exposure of the face?”
[Taken from “Four Essays On The Obligation Of Veiling” Ch. 2: An Essay On Hijaab, p. 29]
(1) As the shaykh mentions elsewhere: “There is no doubt that the face is the place of attraction and beauty and from where temptation is derived.” [Ibid. p.31]