Question Summary:
Is a sister’s husband mahram?

Question Detail:

I came across some argument and I would like to know if your sister’s husband is your mahram.  And can Haj be performed with him?

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
 
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
 
Allah Taā’la is All-Wise and His commands are full of wisdom.  The fulfillment of Allah’s commands guarantees a peaceful and enjoyable life.  Allah Taā’la says in the Glorious Quran:
من عمل صالحا من ذكر او انثى وهو مؤمن فلنحيينه حياة طيبة (سورة النحل, رقم الاية 97)
Whoever, male or female, has done righteous deeds, while a believer, We shall certainly make him live a good life (Quran: 16/97)
 
Today evils such as immodesty, adultery, and avenues leading to these sins are so widespread and have become a norm in society, resulting in the destruction of lives and the foundation of families.  Adhering to Allah’s Deen is the only force that will combat such vices.   When the gazes of men will be lowered and women will not portray their beauty in public, abiding by the laws of hijab, then these evils will vanish. Allah Taā’la says:
بل نقذف بالحق على الباطل فيدمغه فاذا هو زاهق (سورة الانبياء, رقم الاية 18)
Instead, We launch the truth against the falsehood, which smashes it, and in no time it is nothing (Quran: 21/18)
 
At the outset, hijāb is ordained in order to protect the chastity of women from non-mahram (strange) men.  The brother-in-law (sister’s husband) is classified by Sharīah as non-mahram.  Therefore observing hijab from the brother-in-law is necessary and traveling with him alone in the absence of a mahram for Haj or any other journey is impermissible. [1]  [2] In fact, extra precaution is necessary in regards to the brother-in-law.  Since he is part of the family, the avenues to commit sin are easily accessible compared to a complete stranger.  This will lead to the occurrence of misery and hatred within the family and will result in a complete breakdown.  There are many incidents where the laws of hijab and segregation were flouted.  Married men and women got into illicit relationships with even family members and that has caused much pain and grief in the family and also total breakdown in family relationship.  While the injunctions of Islam are very accommodating, at the same time they are very cautious and protecting.  We should always guard ourselves against our Nafs and Shaitān.   
 
                
 
And Allah Ta’āla Knows Best
Mawlana Abdul Azeem bin Abdur Rahman,
Student Darul Iftaa
US
 
Checked and Approved by,
Mufti Ebrahim Desai.
www.daruliftaa.net