(58) باب نِكَاحِ مَا نَكَحَ الآبَاءُ .
It was narrated that Al-Bara' said:
"I met my maternal uncle who was carrying a flag (for an expedition) and I said: 'Where are you going?' He said: 'The Messenger of Allah is sending me to a man who has married his father's wife after he died, to strike his neck or kill him.'"
Reference: Sunan an-Nasa'i 3331
In-book reference: Book 26, Hadith 136
English translation: Vol. 4, Book 26, Hadith 3333