First of all, it should be clear that Hijab is the proper Islamic dress code, which is primarily intended to safeguard the modesty, dignity and honor of men and women. Hijab is a duty Allah Almighty prescribed for the Muslim woman, and she has to carry out that duty in compliance with the order of Allah, and showing her sincere faith in Allah, for He says: “And it becometh not a believing man or a believing woman, when Allah and His Messenger have decided an affair (for them), that they should (after that) claim any say in their affair.” (Al-Ahzab 33: 36)
So, it is clear that Allah Almighty has obliged Muslim women to wear hijab in order to preserve them from bedizenment which would definitely make them prone to harassment and render them an easy prey for depraved men with lusty motives. This means that hijab is a means of protection for women’s honor and dignity.

Sheikh Yusuf Al-Qaradawi, in his well known book, the Lawful and the Prohibited in Islam stated that: “Almighty Allah says: “That they should…not display their adornment, except that which is apparent of it.” (An-Nur 24:31). The adornment of women includes both natural features such as the face, hair, and other attractive parts of the body, and artificial enhancement of beauty, such as the dress, ornaments, make-up, and the like. In this noble ayah Allah commands women not to show their adornment “except that which is apparent of it.”

There is some difference of opinion among scholars concerning the extent of this exception. Does it mean what is exposed by necessity and without intention, for example, if the wind exposes some part? Or does it mean what is customarily, or instinctively, or by its very nature exposed?

The majority of the early Muslim jurists accept the latter meaning. Ibn ‘Abbas interprets “except what is apparent of it” to mean kohl and a ring, and Anas has said something similar; the permissibility of showing the face and hands is implicit in the permissibility of showing kohl and a ring. Sa’id ibn Jubayr, ‘Ata and al-Awza`i have stated explicitly that the showing of the face and hands is permissible. ‘Aishah, Qatadah, and others have added bracelets to what may be shown of the adornments; this interpretation implies that a part of the arm may also be shown. Various scholars have allowed the exposure of the lower part of the arm up to a length varying between about four inches to one-half of the arm.

On the other hand, others such as ‘Abdullah ibn Mas’ud, have restricted the application of “what is apparent” to what necessarily appears, such as the outer garment (abaya, jilbab, chaddor, burqa, and the like). My own preference lies with that group of the Companions and their immediate followers who include the face, the hands, and their ordinary adornments, such as kohl and a ring in the application of the Qur’anic phrase, “except that which is apparent of it.”

This permissibility, however, excludes such cosmetics which women today use for their cheeks, lips and nails. We consider these cosmetics to be excessive, and they must not be used except within a woman’s own home when non-mahrem men are present. The aim of women in using these cosmetics when going out of the house is obviously to attract the attention of men, which is haram. At the same time, however, the interpretation of “what is apparent” as being the outer garment or covering is not acceptable, for this is not something which can possibly be concealed so that an exemption must be made; similarly, what the wind blows cannot be controlled, whether an exemption is made or not. What strikes the mind is that the purpose of the exemption was to provide some concession for the believing woman by permitting her to show something which it is possible to conceal. Reason would indicate that it is the face and hands which are exempted from covering.

Assuredly a woman is permitted to show her face and hands because covering them would be a hardship on her, especially if she must go out on some lawful business. For example, a widow may have to work to support her children, or a woman who is not well-off may have to help her husband in his work; had covering the face and hands been made obligatory, it would have occasioned such women hardship and distress. Al-Qurtabi says,
It seems probable that, since the face and hands are customarily uncovered, and it is, moreover, required that they be uncovered during acts of worship such as salat and hajj, the exemption (referred to in the verses ofSurat an-Nur) pertains to them. This conclusion is supported by what Abu Dawud has transmitted on the authority of ‘A’ishah. She said that ‘Asmaa’, the daughter of Abu Bakr, once came to the Prophet (peace and blessings be upon him) wearing transparent clothes. The Prophet (peace and blessings be upon him) turned his face away from her and told her, ‘Asmaa’, when a woman begins to menstruate, nothing should be seen of her except this and this,’ and he pointed to his face and hands.

In addition to this, we may infer from Allah’s words, “Tell the believing men that they should lower their gazes,” that the faces of the women of the Prophet’s time were not veiled. Had the entire body including the face been covered, it would have made no sense to command them to lower their gaze, since there would have been nothing to be seen.

In spite of all this, however, because of the widespread immorality and laxity in obeying the Islamic injunctions in our time, the best thing for the Muslim woman is to conceal all her adornments including her face if she can. Obviously, more caution in this regard is necessary for a woman who is beautiful. Allah Almighty also says,“…That they should draw their head-coverings over their bosoms….” (An-Nur 24:31)

It is obligatory for the Muslim woman to cover her head, breasts, and neck completely so that nothing of them can be seen by onlookers. In addition, Allah Almighty says, “…And not display their adornment except to their husbands or their fathers….” (An-Nur 24:31)

This injunction prohibits women to show their concealed adornments, such as the ears, hair, neck, breasts, or ankles, to men who are outside the mahrem relationship, before whom they are permitted to expose only the face and hands (of “that which is apparent”).”

Having clarified the above, it becomes clear that hijab is an obligation upon Muslim women which means that all woman’s body is `Awrah except what is (ordinarily) apparent which refers to the face and hands as interpreted by the majority of Muslim scholars.