Hijab of a Muslim woman

(1) Allaah (Subhaanahu wa Ta’aala) says in Surat an-Nur (24:31):

وقل للمؤمنات يغضضن من أبصارهم ويحفظن فروجهن ولا يبدين زينتهن إِلا ما ظهر منها وليضربن بخمرهن على جيوبهن ….

“And tell the believing women to lower their gaze (from looking at forbidden things), and protect their private parts (from illegal sexual acts, etc.) and not to show off their adornment except only that which is apparent (like face, palms of hands, or outer dress like veil, gloves, head-cover, apron, etc..) and draw their veils all over Juyubihinna (necks and bosoms, etc.).”

(2) Allaah (Subhaanahu wa Ta’aala) said in Surat al-Ahzaab (33:59):

يا أيها النبي قل لأزواجك وبناتك ونساء المؤمنين يدنين عليهن من جلابيبهن

“O Prophet! Tell your wives and your daughters and the women of the believers to draw their cloaks all over their bodies.”

(3) If a woman intends to go out from the house, she has to wear her Khimar and wear the Jilbab on top of the Khimar, because this covers more and conceals her body, the size of her head and her shoulders.

(4) ‘Aishah (Radia-Allaahu ‘anha) said: “The woman should pray in three garments, Dir’ (a garment) + Khimar + Jilbab.” [Reported by Sa’d with conditions set by Muslim with a correct chain]

Also Ibn ‘Umar (Radia-Allaahu ‘anhuma) narrated a similar Hadeeth. [Reported by Ibn Abi Shaibah]