Mustadrak al-Hakim — Hadith 6622

It is narrated from Musa bin Uqbah that Ka'b bin Zuhayr (may Allah be pleased with him) recited his ode "Banat Su'ad" to the Prophet (peace and blessings be upon him) in his mosque in Madinah. When he reached these words of his: "Indeed, the Messenger (peace and blessings be upon him) is a sword from which light is sought, a drawn, naked sword among the swords of Allah, among young men of Quraysh (whom he praised), one of whom said in the valley of Makkah (at the time of emigration): Depart from here (and they stood firm)," at this the Messenger of Allah (peace and blessings be upon him) pointed with his sleeve towards the people, that they should listen attentively to his words. The narrator says: Before this, (Ka'b's brother) Bujayr bin Zuhayr had written to his brother Ka'b bin Zuhayr bin Abi Sulma, warning him (of an evil end) and inviting him to Islam, and in it he said these verses: "Who will convey this message of mine to Ka'b: will you give some thought to that (religion) which you wrongly censure, though it is the firmest path? Turn to Allah alone, not to al-Uzza and al-Lat, so that when the time of salvation comes you may be saved and find safety, on the Day when no one will escape and be delivered from the Fire except a Muslim pure of heart. For the religion of Zuhayr is nothing but falsehood, and the religion of Abu Sulma is forbidden to me."
This is a narration whose chains were collected by Ibrahim bin al-Mundhir al-Hizami. As for the narration of Muhammad bin Fulayh from Musa bin Uqbah and the narration of al-Hajjaj bin Dhi al-Ruqaybah, both are sahih (authentic), and Muhammad bin Ishaq al-Qurashi mentioned it in brief in al-Maghazi.