Musnad Ahmad 785:4

Abu Ahmad narrated to us, Abdullah—meaning Ibn Abd al-Rahman ibn Ya'la ibn Ka'b al-Thaqafi al-Ta'ifi—narrated to us, he said: I heard 'Amr ibn al-Sharid narrating from his father, who said: The Messenger of Allah (peace and blessings of Allah be upon him) asked me to recite the poetry of Umayyah ibn Abi al-Salt, so I recited it to him. Every time I recited a verse to him, he would say, "Go on." Until I had recited one hundred rhymes to him, he then said, "He almost became a Muslim."