Question:
Assalamualaikum wrm.wbt.,
What is the ruling of in-laws marrying each other?
Answer:
Waalaikumussalam wrm. wbt.
Alhamdulillah, praise and thanks to Allah for the countless blessings He has blessed us all with. Blessings and salutations to the Prophet Muhammad PBUH, his wives, his family, companions and all those that follow his teachings to the day of judgement.
We will present examples for the situations as the following:
First situation: Ahmad marries Aminah. Then, Ahmad’s father; Ali (Aminah’s father in-law) marries Aminah’s mother; Fatimah (Ahmad’s mother in-law).
Second situation: Ali and Fatimah (Ahmad’s father and Aminah’s mother) first married each other. Then, Ahmad and Aminah (their respective step children) marry each other.
The marriage between in-laws is valid and permissible regardless of whether the marriage happened when their children’s marriage still continues or even after they had divorced. Likewise, the marriage is valid and permissible regardless if it happened when the marriage of their parents (Ali and Fatimah) still endures or after they had divorced.
Syeikh al-Bujairimi Rahimahullah said:
أَنَّهَا لَا تَحْرُمُ بِنْتُ زَوْجِ الْأُمِّ وَلَا أُمُّهُ وَلَا بِنْتُ زَوْجِ الْبِنْتِ وَلَا أُمُّهُ وَلَا أُمُّ زَوْجَةِ الْأَبِ وَلَا بِنْتُهَا وَلَا أُمُّ زَوْجَةِ الِابْنِ وَلَا بِنْتُهَا وَلَا زَوْجَةُ الرَّبِيبِ، لِخُرُوجِهِنَّ عَنْ الْمَذْكُورَاتِ
“Indeed, it is not haram to marry with the daughter of a mother’s husband (step-sibling), it is also not haram with the mother of the husband’s mother (step-grandmother), it is also not haram with the child of the mother of the child’s husband (one’s child in-law), it is also not haram with the mother of husband’s mother (step-grandmother), it is also not haram with daughter of husband’s wife (step-sibling), it is also not haram with the mother of wife to a child (the child’s in-law), it is also not haram with the child of the wife’s child (the child the step of the child), and it is also not haram with the wife of a step-child for they are excluded from those who are stated as haram to be married.” (See Hashiah al-Bujairimi ‘ala al-Khatib, 3/423)
Whereas, in terms of their familial status, they are bound with the rulings which has been set by syara’ such as matters related with mahram, inheritance, wali and others.