What specific text commands women to wear hijab?
Hadith (the tradition of the Prophet) says that with regard to the veiling of women, the Prophet’s companion Hazrat Umar bin Al-Khattab used to say, ‘O Allah’s Apostle! I wish you ordered your wives to cover themselves from the men because good and bad ones talk to them.’ So Allah revealed the verse of the veiling of women. This text is found in Bukhari, vl, bk 8, sunnah 395.
Another verse that supports the veiling of women can be found in Surah XXXIII, “O Prophet! Tell thy wives and thy daughters and the women of the believers to draw their cloaks close around them. That will be better, so that they may be recognized and not annoyed.”