Jami At Tirmidhi
1362
Sahih+2

Narrated Al-Bara':"My maternal uncle Abu Burdah Ibn Niyar passed by me and he had a flag with him. I said: 'Where are you going ?' He said: 'the Messenger of Allah (ﷺ) dispatched me to a man who married a woman his father had married to: that I should bring him his head

SahihAhmad Muhammad Shakir
SahihAl-Albani