Hilal bin Yasaf reported,

An old man rushed and slapped a servant girl of his. Suwayd bin Muqarin said to him, "Could you find nothing to strike but the noblest part of her, her face? I remember when I was one of seven brothers from the sons of Muqarin, and we had only a single servant girl. The youngest of us slapped her, and the Messenger of Allah ﷺ ordered us to set her free."

Azami 14008

Sahih

عن هلال بن يساف

قال عجل شيخ فلطم خادما له، فقال له سويد بن مقرن: عجز عليك إلا حر وجهها، لقد رأيتني سابع سبعة من بني مقرن ما لنا خادم إلا واحدة، لطمها أصغرنا، فأمرنا رسول الله ﷺ أن نعتقها.

الأعظمي 14008صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Superior moral conduct
Chapter
Noble character
Section
Expiation for one who strikes his slave is to free him
Numbering
Jami al-Kamil 14008 (2nd edition)
Azami 14008