The proof that would come to mind when talking about the obligation of hijab is the verses 30-31 in Surah 24 of the Holy Qur’an, which give the meaning of:
*{Tell the believing men to lower their gaze and be modest. That is purer for them. Lo! Allah is Aware of what they do. And tell the believing women to lower their gaze and be modest, and to display of their adornment only that which is apparent, and to draw their veils over their bosoms, and not to reveal their adornment save to their own husbands or fathers or husbands’ fathers, or their sons or their husbands' sons, or their brothers or their brothers' sons or sisters’ sons, or their women, or their slaves, or male attendants who lack vigor, or children who know naught of women's nakedness. And let them not stamp their feet so as to reveal what they hide of their adornment. And turn unto Allah together, O believers, in order that ye may succeed.}*
See also verse number 59 in Surah, which give the meaning of:
*{O Prophet! Tell thy wives and thy daughters and the women of the believers to draw their cloaks close round them [when they go abroad]. That will be better, that so they may be recognized and not annoyed. Allah is ever Forgiving, Merciful.}*
Heres some of the Virtues of the Hijaab:
http://www.islamway.com/sisters/modules ... le&sid=329Obediance
Iffah -Modesty
Tahara -Purity
Shield
Taqwah -Righteousness
Eemaan -Belief or Faith
Haya' -Bashfulness
Finally...The hijab is Gheerah
P.S Allah Knows Best
JazakAllah Khair sis