Musnad Ahmad 175:23

Abu al-Yaman narrated to us, he said: Shu’ayb informed us, from al-Zuhri, he said: Abu Bakr ibn ‘Abd al-Rahman ibn al-Harith ibn Hisham narrated to me, that Marwan ibn al-Hakam informed him, that ‘Abd al-Rahman ibn al-Aswad ibn ‘Abd Yaghuth informed him, that Ubayy ibn Ka’b al-Ansari informed him, that the Prophet, peace and blessings of Allah be upon him, said: "Indeed, some poetry is wisdom." And Bashir ibn ‘Abd al-Rahman ibn Ka’b used to narrate that Ka’b ibn Malik used to narrate that the Prophet, peace and blessings of Allah be upon him, said: "By the One in whose hand is my soul, it is as if you are pelting them with arrows by what you say to them in poetry."