Narrated AbuRafi':

The Quraysh sent me to the Apostle of Allah , and when I saw the Apostle of Allah , Islam was cast into my heart, so I said: Apostle of Allah, I swear by Allah, I shall never return to them. The Apostle of Allah replied: I do not break a covenant or imprison messengers, but return, and if you feel the same as you do just now, come back. So I went away, and then came to the Prophet and accepted Islam.