Sunan Ibn Majah
2608
Hasan Sahih+2

It was narrated from Mu'awiyah bin Qurrah that his father said:“The Messenger of Allah (ﷺ) sent me to a man who had married his father's wife after he died, to strike his neck (execute him) and confiscate his wealth.”

Hasan SahihAl-Albani
Hasan SahihMuhammad Fouad Abd al-Baqi