In the name of Allah, We praise Him, seek His help and ask for His forgiveness. Whoever Allah guides none can misguide, and whoever He allows to fall astray, none can guide them aright. We bear witness that there is none worthy of worship but Allah Alone, and we bear witness that Muhammad (saws) is His slave-servant and the seal of His Messengers.
Allah says in the Holy Quran Chapter 33 Surah Ahzaab verse 59:
O Prophet, enjoin your wives and daughters, and the believing women, that they should cast their outer garments over their persons. It is expected that they will thus be recognized, and not molested. Allah is Oft-Forgiving, Most Merciful.
Allah says in the Holy Quran Chapter 24 Surah An-Noor verse 31:
And O Prophet, enjoin the believing women to restrain their gaze and guard their private parts and not to display their ‘zeenata hunna’ (beauty, adornment, etc.) except that which is displayed of itself, and to draw their veils over their bosoms and not to display their ‘zeenata hunna’ (beauty, adornment, etc.) except before their husbands, their fathers, the fathers of their husbands, their sons and the sons of their husbands, their brothers, their brothers sons, their sisters’ sons, their female associates, and those in their possession and male attendants incapable of sexual desire, and those boys who have not yet attained knowledge of sexual matters. Also forbid them to stamp their feet on the ground lest their hidden ornaments should be displayed.
Allah Subhanah has directed the Command towards the Prophet (saws) commanding him to enjoin his wives, his daughters and the believing women that when in the presence of non-mehram males, they should cast their outer garments over their full body. All the schools of thought in Islam are unanimous in their opinion that the casting of an outer garment or ‘jilbaab’ is absolutely obligatory upon every believing woman who has passed the age of puberty.