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””"
SahihSahihSahihBook 15 · Hadith 42