Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said to Ibn al-Nawwahah: "I heard the Messenger of Allah (peace and blessings be upon him) say: If you were not an envoy, I would have killed you. But today you are no longer an envoy." Then he said: "O Harashah! Get up and strike off his neck." So he got up to him and struck off his neck.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8926