Sahih Muslim , Book 15, Hadith 4086 (USC-MSA) ⓘ

Abu Mas'ud al-Badri reported: I was beating my slave with a whip when I heard a voice behind me: Understand, Abu Masud; but I did not recognise the voice due to intense anger. He (Abu Mas'ud) reported: As he came near me (I found) that he was the Messenger of Allah and he was saying: Bear in mind, Abu Mas'ud; bear in mind. Abu Mas'ud. He (Aba Maslad) said: threw the whip from my hand. Thereupon he (the Holy Prophet) said: Bear in mind, Abu Mas'ud; verily Allah has more dominance upon you than you have upon your slave. I (then) said: I would never beat my servant in future.

حَدَّثَنَا أَبُو كَامِلٍ الْجَحْدَرِيُّ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، - يَعْنِي ابْنَ زِيَادٍ - حَدَّثَنَا الأَعْمَشُ، عَنْ إِبْرَاهِيمَ التَّيْمِيِّ، عَنْ أَبِيهِ، قَالَ قَالَ أَبُو مَسْعُودٍ الْبَدْرِيُّ كُنْتُ أَضْرِبُ غُلاَمًا لِي بِالسَّوْطِ فَسَمِعْتُ صَوْتًا مِنْ خَلْفِي ‏"‏ اعْلَمْ أَبَا مَسْعُودٍ ‏"‏ ‏.‏ فَلَمْ أَفْهَمِ الصَّوْتَ مِنَ الْغَضَبِ - قَالَ - فَلَمَّا دَنَا مِنِّي إِذَا هُوَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَإِذَا هُوَ يَقُولُ ‏"‏ اعْلَمْ أَبَا مَسْعُودٍ اعْلَمْ أَبَا مَسْعُودٍ ‏"‏ ‏.‏ قَالَ فَأَلْقَيْتُ السَّوْطَ مِنْ يَدِي فَقَالَ ‏"‏ اعْلَمْ أَبَا مَسْعُودٍ أَنَّ اللَّهَ أَقْدَرُ عَلَيْكَ مِنْكَ عَلَى هَذَا الْغُلاَمِ ‏"‏ ‏.‏ قَالَ فَقُلْتُ لاَ أَضْرِبُ مَمْلُوكًا بَعْدَهُ أَبَدًا ‏.‏