Amr ibn Shareed radiyallahu anhu reports that his father said, I once accompanied Rasoolullah sallallahu alaihe wasallam and sat behind him on a conveyance. I recited a hundred couplets of Umayyah ibn Sault to Rasoolullah sallallahu alaihe wasallam. After reciting a couplet Rasoolullah sallallahu alaihe wasallam said "continue" till I recited a hundred couplets. In the end Rasoolullah sallallahu alaihe wasallam said, "He (Umayyah) was close to accepting Islam."
English reference: Book 36, Hadith 238
Arabic reference: Book 37, Hadith 249