In the Name of Allah, the Most Beneficent, the Most Merciful.

Question / Is Hijab an obligation?

Answer / Hijab is an obligation and the proofs of this are found in both Quran as well as Hadith. Amongst the proofs found in the Holy Quran are the following verses: 

“O Prophet! say to your wives and your daughters and the women of believers that they lay down upon them their over-garments; this will be more proper, that they may be known, and thus they will not be given trouble; and Allah is Forgiving, Merciful” (33:59). 

“And say to the believing women that they cast down their looks and guard their private parts and do not display their ornaments except what appears thereof, and let them wear their head-coverings over their bosoms, and not display their ornaments except to their husbands or their fathers, or the fathers of their husbands, or their sons, or the sons of their husbands, or their brothers, or their brothers' sons, or their sisters' sons, or their women, or those whom their right hands possess, or the male servants not having need (of women), or the children who have not attained knowledge of what is hidden of women; and let them not strike their feet so that what they hide of their ornaments may be known; and turn to Allah all of you, O believers! so that you may be successful” (24:31). 

“And (as for) women advanced in years who do not hope for a marriage, it is no sin for them if they put off their outer-garments without displaying their ornaments; and if they restrain themselves it is better for them; and Allah is Hearing, Knowing” (24:60). 

Amongst the many proofs found in Hadith are the following: 

In a lengthy Hadith by the holy Prophet (peace be upon him and his pure family), in which he described what he had seen in hellfire when he was ascended to heavens, he said: “I saw a woman hanging from her hair and her brain was boiling” When his daughter Fatima al-Zahra (peace be upon her) asked him what was her doing to suffer such torture he (peace be upon him and his pure family) said: “she would not cover her hair from men.” (Bihar al-Anwar by al-Majlisi, vol. 08, pg. 309). 

Imam al-Ridha (peace be upon him) was asked whether it is lawful to look at the hair of one’s sister-in-law (wife’s sister), the Imam (peace be upon him) replied: “No, unless if she is an elderly woman (i.e. known as Qawa’id)” the man asked whether the ruling is the same regarding one’s sister-in-law and any other non-mahram woman, the Imam (peace be upon him) replied: “Indeed”. (Wasa’il al-Shia, vol. 02, pg. 199). 

Imam al-Ridha (peace be upon him) said in a written answer to a number of inquiries sent to him: “Looking at the hair of married and non-married women is prohibited….” (Wasa’il al-Shia, vol. 02, pg. 193).