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. (Using translation from Abū Dāʾūd 2652)
عَنِ الْفُرَاتِ بْنِ حَيَّانَ وَكَانَ رَسُولُ اللهِ ﷺ قَدْ أَمَرَ بِقَتْلِهِ وَكَانَ عَيْنًا لِأَبِي سُفْيَانَ وَحَلِيفًا أَظُنُّهُ قَالَ لِرَجُلٍ مِنَ الْأَنْصَارِ فَمَرَّ عَلَى حَلْقَةٍ مِنَ الْأَنْصَارِ فَقَالَ إِنِّي مُسْلِمٌ فَقَامَ رَجُلٌ مِنْهُمْ فَقَالَ يَا رَسُولَ اللهِ يَقُولُ إِنِّي مُسْلِمٌ فَقَالَ رَسُولُ اللهِ ﷺ إِنَّ مِنْهُمْ رِجَالًا نَكِلُهُمْ إِلَى إِيمَانِهِمْ مِنْهُمُ الْفُرَاتُ بْنُ حَيَّانَ