Volume 1, Book 8, Number 451:
Narrated Abu Huraira:
The Prophet sent some horsemen to Najd and they brought a man called Thumama bin Uthal from
Bani Hanifa. They fastened him to one of the pillars of the mosque. The Prophet came and ordered
them to release him. He went to a (garden of) date-palms near the mosque, took a bath and entered
the, mosque again and said, “None has the right to be worshipped but Allah an Muhammad is His
Apostle (i.e. he embraced Islam).”