Sahih Muslim
The Book of Poetry (Kitab Al-Shir)
Book Number: 028 / Hadith Number: 5603
'Amr b. Sharid reported on the authority of his father that Allah's Messeniger (may peace be upon him) asked him to recite poetrv, the rest of the hadith is the same, out with this addition:" He (that is Umayya b. Abu Sharid was about to become a muslim and in the hadith transmitted on the authority, of Ibn Mahdi (the words are)" He was almost a Muslim in his poetry."