Maliks Muwatta Book 28, Hadith Number 23B.

Section : Marriage to Mothers of Women with Whom One has had Sexual Relations in a Disapproved Manner.

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.”