Allah, the Most High says:
“O Prophet! Tell your wives and daughters and believing women that they should cast their Jalaabeeb [outer- garments] over their persons. That is most convenient that they should be known (as such) and not molested. And Allah is Most Forgiving and Most Merciful.” (Surah al-Ahzaab, verse 59).
The above verse is clear in determining that it is obligatory (Fardh) upon a woman to cover herself with a Jilbaab. This leaves us with a question, what is a Jilbaab?
It is stated in Lisaan al-Arab:
“Jilbaab, plural of Jalaabeeb: an outer garment or a cloak with it a woman covers her head and chest. And it is said: It is a long cloak that covers a woman completely." (Ibn Manzur, Lisan al-Arab, 2/317).
Sayyiduna Ibn 'Abbaas (may Allah be pleased with him) states: “Jilbab is long cloak that covers a woman from her head to her feet.” (Ruh al-Ma’ani, 22/88).
The Two Types of Jilbaab
There are two kinds of Jilbaab:
1. A Jilbaab which is worn from the head down, all the way down to the feet, wearing just one cloth. This type of Jilbaab is predominant in Saudi Arabia, Iran and such places.
2. Other sisters wear a Jilbaab which is detached from the Khimaar (head-cover), and flows from the shoulder downward. If a sister wears this kind of Jilbaab then she must insure that her Hijaab is big enough and covers her hair, ears, neck and chest properly. If she is complacent in doing so, then a day is near when she will be accountable to her Lord.
Let's contemplate the following narration:
'After the revelation of this verse, many female Companions (Allah be pleased with them all) used to emerge outside their homes with complete reticence as though birds were sitting on their heads. They used to cover themselves with long black cloaks.' (See: Ruh al-Ma’ani, 22/89).
The above and other interpretations of Jilbaab are clear that a Jilbaab is the outer garment that women must wear when emerging in front of strangers, be it outside or within the home. This garment must be wide, loose, and modest and cover the body completely. The scholars differed over whether or not the face-veil is included, without a doubt it is highly recommended.