Most Muslims are familiar with the various reasons that Allah has required women to wear hijab: The hijab reflects modesty, purity and respect; it lessens temptation so that more serious sins will be avoided; it protects women from the harm and molestation of evil men; a woman who wears hijab will be evaluated for her intelligence and skills rather than her appearance.
One important aspect that is often overlooked, however, is that the hijab is a symbol of Muslim identity. A woman who covers her head is making a statement that she is a member of the Muslim community and that she follows a particular code of moral conduct.
Allah says: "O Prophet, tell your wives and daughters and the believing women to draw their outer garments around them. That is more suitable that they will be known (as Muslims and chaste believing women) and not be abused." [Qur'an, 33:59]