Malik said that a man who had committed fornication with a woman and the hadd-punishment had been applied to him for it, could marry that woman's daughter and his son could marry the woman herself if he wished. That was because he had haram relations with her, and the relations Allah had made haram were from the relations made in a halal manner or in a manner resembling marriage. Allah, the Blessed, the Exalted, said, "Do not marry the women your fathers have married. " (Sura 4 ayat 21)

Malik said, "If a man were to marry a woman in her idda-period in a halal marriage and have relations with her, it would be haram for his son to marry the woman. That is because the father married her in a halal manner, and the hadd-punishment would not have been applied to him. Any child who was born to him would be attached to him as the father. Just as it would be haram for the son to marry a woman whom his father had married in her idda-period and had relations with, so the woman's daughter would be haram for the father if he had had sexual relations with her."
Muwatta Malik Book 28, Hadith 25
← Previous Hadith Yahya related to me from Malik from more than one source that when Abdullah ibn Masud was in Kufa, he was asked for an opinion about marrying the mother after marrying the daughter when the marriage with the daughter had not been consummated. He permitted it. When Ibn Masud came to Madina, he asked about it and was told that it was not as he had said, and that this condition referred to foster-mothers. Ibn Masud returnedto Kufa,and he had just reached his dwelling when the man who had asked him for the opinion came to visit and he ordered him to separate from his wife.

Malik said that if a man married the mother of a woman who was his wife and he had sexual relations with the mother then his wife was haram for him, and he had to separate from both of them. They were both haram to him forever, if he had had sexual relations with the mother. If he had not had relations with the mcther, his wife was not haram for him, and he separated from the mother.

Malik explained further about the man who married a woman, and then married her mother and cohabited with her, "The mother will never be halal for him, and she is not halal for his father or his son, and any daughters of hers are not halal for him and so his wife is haram for him."

Malik said, "Fornication however, does not make any of that haram because Allah, the Blessed, the Exalted, mentioned 'the mothers of your wives,' as one whom marriage made haram, and he didn't mention the making haram by fornication. Every marriage in a halal manner in which a man cohabits with his wife, is a halal marriage. This is what I have heard, and this is how things are done among us."

Muwatta Malik Book 28, Hadith 24 Next Hadith → Yahya related to me from Malik from Nafi from Abdullah ibn Umar that the Messenger of Allah, may Allah bless him and grant him peace, forbade shighar, which meant one man giving his daughter in marriage to another man on the condition that the other gave his daughter to him in marriage without either of them paying the bride-price.

Muwatta Malik Book 28, Hadith 26