Sahih Muslim 4299
صحيح مسلم#4299SahihZadhan reported that Ibn Umar called his slave and he found the marks (of beating) upon his back. He said to him:I have caused you pain. He said: No. But he (Ibn Umar) said: You are free. He then took hold of something from the earth and said: There is no reward for me even to the weight equal to it. I heard Allah's Messenger (ﷺ) as saying: He who beats a slave without cognizable offence of his or slaps him (without any serious fault), then expiation for it is that he should set him free
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 27:46