I was beating a slave boy of mine when I heard a voice behind me saying, "Know, Abu Masud, that Allah has more power over you than you have over him."I turned around and there was the Messenger of Allah ﷺ. I said, "Messenger of Allah, he is free for the sake of Allah."He said, "Had you not done so, the Fire would have scorched you," or "the Fire would have touched you."
كنت أضرب غلاما لي، فسمعت من خلفي صوتا: اعلم أبا مسعود: الله أقدر عليك منك عليه. فالتفت، فإذا هو رسول الله ﷺ، فقلت: يا رسول الله، هو حر لوجه الله، فقال: أما لو لم تفعل للفحتك النار، أو لمستك النار.
Muslim narrated it in the book of vows (1659:35) from Abu Kurayb Muhammad bin Ala, who said, Abu Muawiya narrated to us, Amash narrated to us, from Ibrahim Taymi, from his father, from Abu Masud, and he related it. In the version of Abdul-Wahid bin Ziyad, from Amash, "Know, Abu Masud, that Allah has more power over you than you have over this boy."