وَقَالَ مَالِكٌ فِي الرَّجُلِ يَتَزَوَّجُ الْمَرْأَةَ، ثُمَّ يَنْكِحُ أُمَّهَا، فَيُصِيبُهَا : إِنَّهُ لَا تَحِلُّ لَهُ أُمُّهَا أَبَدًا، وَلَا تَحِلُّ لِأَبِيهِ، وَلَا لِابْنِهِ، وَلَا تَحِلُّ لَهُ ابْنَتُهَا، وَتَحْرُمُ عَلَيْهِ امْرَأَتُهُ
Imam Malik, may Allah have mercy on him, said: However, if he does not have intercourse with the mother, then he should leave her, and her daughter will remain lawful for him.
Imam Malik, may Allah have mercy on him, said: If a man marries a woman, then marries her mother and has intercourse with her, then the mother’s mother will also become unlawful, and the mother will remain unlawful for that man’s father and son.