Musnad Ahmad 785:11

Azhar ibn al-Qasim narrated to us, Abdullah ibn Abd al-Rahman ibn Ya'la ibn Ka'b al-Ta'ifi narrated to us, from Amr ibn al-Sharid, from his father, that the Messenger of Allah (may Allah bless him and grant him peace) asked him to recite the poetry of Umayyah ibn Abi al-Salt. He said: So he recited one hundred rhymes to him. He did not recite anything to him except that he said, "Go on, go on." Until, when he had exhausted one hundred rhymes, he said, "He almost became a Muslim."