Amr bin al-Sharid narrates from his father (may Allah be pleased with him): I recited to the Prophet (peace and blessings be upon him) a hundred verses of Umayyah bin Abi al-Salt, and he (peace and blessings be upon him) kept saying: "Recite more." Then he said: "He very nearly became a Muslim."
Al-Shafi'i said: "He (peace and blessings be upon him) listened to rajaz or poetry."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 21030