Musnad Abu Ya'la al-Mawsili 160:152

Bishr ibn Sayhan narrated to us, Amr ibn Muhammad al-Ruzayni narrated to us, and he said: I have never seen the likes of him with my own eyes at all. Sufyan al-Thawri narrated to us, from a man, from Sa'id ibn Abi Sa'id al-Maqburi, from his father, from Abu Hurayrah, who said: When Thumamah accepted Islam, the Messenger of Allah (may Allah bless him and grant him peace) commanded him to perform ghusl (a ritual bath) and to pray two rak'ahs.