He came to Abdullah and said, "There is no grudge between me and any of the Arabs, but I passed by a mosque belonging to Banu Hanifa and found them professing belief in Musaylima."So Abdullah sent for them, and they were brought before him. He called on them to repent, and they all did except Ibn al-Nawaha.Abdullah said to him, "I heard the Messenger of Allah ﷺ say, 'Were it not that you are an envoy, I would have struck off your neck.' Today you are no envoy."He then ordered Qarada bin Kaab, who struck off his neck in the marketplace. Abdullah then announced, "Whoever wishes to look upon Ibn al-Nawaha slain in the marketplace, let him do so."
حدثنا محمد بن كثير أخبرنا سفيان عن أبي إسحق
أنه أتى عبد الله فقال ما بيني وبين أحد من العرب حنة وإني مررت بمسجد لبني حنيفة فإذا هم يؤمنون بمسيلمة فأرسل إليهم عبد الله فجيء بهم فاستتابهم غير ابن النواحة قال له سمعت رسول الله ﷺ يقول لولا أنك رسول لضربت عنقك فأنت اليوم لست برسول فأمر قرظة بن كعب فضرب عنقه في السوق ثم قال من أراد أن ينظر إلى ابن النواحة قتيلا بالسوق
[Its chain is daif] Bayhaqi related it 9/211 from the hadith of Abu Dawud through this route, and Ahmad related it 1/384, and Nasai in al-Kubra, no. 8675, and Ibn Hibban graded it sahih, no. 1629. The hadith has many corroborating narrations in Ahmad 1/396 and Hakim 3/53 and others. Abu Ishaq used "an" without specifying direct transmission.