﴿ وَلَا تَنكِحُوا۟ مَا نَكَحَ ءَابَآؤُكُم مِّنَ ٱلنِّسَآءِ إِلَّا مَا قَدْ سَلَفَ ۚ إِنَّهُۥ كَانَ فَٰحِشَةًۭ وَمَقْتًۭا وَسَآءَ سَبِيلًا ﴾

“AND DO NOT marry women whom your fathers have previously married - although what is past is past: this, verily, is a shameful deed, and a hateful thing, and an evil way.”

He said: (And marry not those women whom your fathers married, except what hath already happened (of that nature) in the past) in the pre-Islamic era. (Lo! It) i.e. marrying the wives of one's father (was ever lewdness) a transgression (and abomination) antagonism, (and an evil way) the worst way to follow. This was revealed about Muhsin Ibn Abi Qays al-Ansari. Allah then showed them the women who are unlawful for them to marry.