Musnad Ahmad 924:3

Abdullah narrated to us, Mansur ibn Bashir narrated to me, Ibrahim ibn Sa'd narrated to us, from al-Zuhri, from Abu Bakr, from Marwan, from Abd al-Rahman ibn al-Aswad ibn Yaghuth, from Ubayy ibn Ka'b: That the Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, some poetry is wisdom."