The Messenger of Allah ﷺ ordered that Furat bin Hayan be killed, for he had been a spy for Abu Sufyan and was an ally of one of the Ansar. He passed by 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 replied, "Among you are Some men whose faith we entrust to them, and Furat bin Hayan is one of them."
حدثنا محمد بن بشار حدثني محمد بن محبب أبو همام الدلال حدثنا سفيان بن سعيد عن أبي إسحق عن حارثة بن مضرب
أن رسول الله ﷺ أمر بقتله وكان عينا لأبي سفيان وكان حليفا لرجل من الأنصار فمر بحلقة من الأنصار فقال إني مسلم فقال رجل من الأنصار يا رسول الله إنه يقول إنى مسلم فقال رسول الله ﷺ إن منكم رجالا نكلهم إلى إيمانهم منهم فرات بن حيان
[Its isnad is daif] Ahmad recorded it, 4/336, from the hadith of Sufyan Thawri, through this route. Ibn Jarud graded it sahih, no. 1058, as did Hakim, according to the standard of the two Sheikhs, 4/366, and Dhahabi agreed with him. Abu Ishaq Sabi is a mudallis and he narrated it using "an" (without an explicit statement of direct hearing).