Narrated Furat ibn Hayyan: The Messenger of Allah (ﷺ) commanded to kill him: he was a spy of AbuSufyan and an ally of a man of the Ansar. He passed a circle of the Ansar and said: I am a Muslim. A man from the Ansar said, Messenger of Allah, he is saying that he is a Muslim. The Messenger of Allah (ﷺ) said: There are people among you in whose faith we trust. Furat ibn Hayyan is one of them

English translation · Sunan Abu Dawud