legal standing of his nikah with his second wife who became a Muslim?

Question

A man named Haamid who was a Christian, married a Christian woman named Saaima, daughter of Siddeeq Maseeh, according to the Christian rituals. Then he became a Muslim and later married his sister in-law named Maryam who is the actual sister of his wife and was also a Christian but had accepted Islaam. Please provide Islamic guidance on this issue whether his marriage with the first wife who is a Christian is still intact or is it voided? And what is the legal standing of his nikah with his second wife who became a Muslim?

Answer

All praise is for Allaah alone, and peace and blessings be upon the one who has no prophet after him.

Allaah the Most High has permitted marrying the women of Ahl al-Kitaab (People of the Book). He (swt) says:

{الْيَوْمَ أُحِلَّ لَكُمُ الطَّيِّبَاتُ وَطَعَامُ الَّذِينَ أُوتُوا الْكِتَابَ حِلٌّ لَكُمْ وَطَعَامُكُمْ حِلٌّ لَهُمْ وَالْمُحْصَنَاتُ مِنَ الْمُؤْمِنَاتِ وَالْمُحْصَنَاتُ مِنَ الَّذِينَ أُوتُوا الْكِتَابَ مِنْ قَبْلِكُمْ إِذَا آتَيْتُمُوهُنَّ أُجُورَهُنَّ مُحْصِنِينَ غَيْرَ مُسَافِحِينَ وَلَا مُتَّخِذِي أَخْدَانٍ }

{This day, good things have been made lawful for you. The food of the people of the Book is lawful for you, and your food is lawful for them, and [permissible for you in marriage are] chaste women from among believers, and chaste women from among those who were given the Book before you, provided you give them their dowers, binding yourself in marriage, neither going for lust, nor having paramours. Whoever rejects Faith, his effort will go to waste and, in the Hereafter, he will be among the losers.} [al-Maa’idah: 5]

Based on this verse, if the husband from a Christian couple becomes a Muslim then his marriage would not be invalidated by the changing of his religion, rather this marriage is intact. So when this marriage is still intact, it is legally Haraam for him to marry the sister of his wife, as it is mentioned the Glorious Qur’aan:

{حُرِّمَتْ عَلَيْكُمْ أُمَّهَاتُكُمْ وَبَنَاتُكُمْ وَأَخَوَاتُكُمْ وَعَمَّاتُكُمْ وَخَالَاتُكُمْ وَبَنَاتُ الْأَخِ وَبَنَاتُ الْأُخْتِ وَأُمَّهَاتُكُمُ اللَّاتِي أَرْضَعْنَكُمْ وَأَخَوَاتُكُمْ مِنَ الرَّضَاعَةِ وَأُمَّهَاتُ نِسَائِكُمْ وَرَبَائِبُكُمُ اللَّاتِي فِي حُجُورِكُمْ مِنْ نِسَائِكُمُ اللَّاتِي دَخَلْتُمْ بِهِنَّ فَإِنْ لَمْ تَكُونُوا دَخَلْتُمْ بِهِنَّ فَلَا جُنَاحَ عَلَيْكُمْ وَحَلَائِلُ أَبْنَائِكُمُ الَّذِينَ مِنْ أَصْلَابِكُمْ وَأَنْ تَجْمَعُوا بَيْنَ الْأُخْتَيْنِ إِلَّا مَا قَدْ سَلَفَ إِنَّ اللَّهَ كَانَ غَفُورًا رَحِيمًا}

{Prohibited to you [for marriage] are your mothers, your daughters, your sisters, your father’s sisters, your mother’s sisters, your brother’s daughters, your sister’s daughters, your [milk] mothers who nursed you, your sisters through nursing, your wives’ mothers, and your step-daughters under your guardianship [born] of your wives unto whom you have intercourse with. But if you have not had intercourse with them, there is no sin upon you. And [also prohibited are] the wives of your sons who are from your [own] loins, and that you take [in marriage] two sisters simultaneously, except for what has already occurred. Indeed, Allah is ever Forgiving and Merciful.}[Al-Nisaa: 23]

Based on this, it is not permissible for a Muslim to marry the sister of his wife. If he has already done so then this nikah is invalid and it has no legal standing. They should get separated immediately and seek Allaah’s forgiveness for this sin.

And Allaah knows best