Sahih Bukhari Volume 7, Book 69, Hadith Number 512.

Narrated By Al-Bara : The Prophet came from Mecca with Abu Bakr. Abu Bakr said “We passed by a shepherd and at that time Allah’s Apostle was thirsty. I milked a little milk in a bowl and Allah’s Apostle drank till I was pleased. Suraqa bin Ju’shum came to us riding a horse (chasing us). The Prophet invoked evil upon him, whereupon Suraqa requested him not to invoke evil upon him, in which case he would go back. The Prophet agreed.