Musnad Ahmad 30:2944

'Abd al-Rahman narrated to us, from Sufyan, who said: 'Abd al-Malik ibn 'Umayr narrated to us, who said: Abu Salamah narrated to us, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The truest word a poet ever said is the word of Labid: 'Indeed, everything except Allah is false.'" And Umayyah ibn Abi al-Salt was on the verge of becoming a Muslim.