From Sahih Muslim (Hadith 4303):
Hilal b. Yasaf reported:We used to sell cloth in the house of Suwaid b. Muqarrin, the brother of Nu'man b. Muqarrin. There came out a slave-girl, and she said something to a person amongst us, and he slapped her. Suwaid was enraged-the rest of the hadlth is the same
Reference: Muslim 4303