Abu Dawud Book 36, Hadith Number 5157.

Narated By Kaladah ibn Hanbal : Safwan ibn Umayyah sent him with some milk, a young gazelle and some small cucumbers to the Apostle of Allah (PBUH) when he was in the upper part of Mecca. I entered but I did not give a salutation. He said: Go back and say: “Peace be upon you”! This happened after Safwan ibn Umayyah and embraced Islam. Amr said: Ibn Safwan told me all this on the authority of Kaladah ibn Hanbal, and he did not say: I heard it from him.