We used to sell milk at the house of Suwayd bin Muqarin. A slave girl belonging to Suwayd came out and spoke to one of our men, and she insulted him, so he slapped her face.Suwayd said, "You slapped her? I remember when I was the seventh of seven brothers, and we had only one servant. One of us slapped her, and the Messenger of Allah ﷺ ordered us to set her free."
حدثنا محمد بن جعفر حدثنا شعبة عن حصين قال سمعت هلال بن يساف يحدث
كنا نبيع اللبن في دار سويد بن مقرن قال فخرجت جارية لسويد فكلمت رجلا منا فسبته فلطم وجهها فقال سويد لطمتها لقد رأيتني وإني لسابع سبعة من إخوتي ما لنا إلا خادم فعمد أحدنا فلطمها فأمرنا رسول الله ﷺ بعتقها
Its isnad is sahih, its narrators are well-known and trustworthy, and they have already been discussed. The hadith was narrated by Muslim 3/1279 in the Book of Faith, Abu Dawud 4/342 no. 5166, and Tirmidhi 4/114 no. 1542, who said, hasan sahih, and Bukhari in Adab al-Mufrad no. 176.