When I was beating my servant, I heard a voice behind me (saying): Abu Mas'ud, bear in mind Allah has more dominance over you than you have upon him. I turned and (found him) to be Messenger of Allah ﷺ. I said: Messenger of Allah, I set him free for the sake of Allah. Thereupon he said: Had you not done that, (the gates of) Hell would have opened for you, or the fire would have burnt you.  

فَسَمِعْتُ مِنْ خَلْفِي صَوْتًا اعْلَمْ أَبَا مَسْعُودٍ لَلَّهُ أَقْدَرُ عَلَيْكَ مِنْكَ عَلَيْهِ فَالْتَفَتُّ فَإِذَا هُوَ رَسُولُ اللَّهِ ﷺ فَقُلْتُ يَا رَسُولَ اللَّهِ هُوَ حُرٌّ لِوَجْهِ اللَّهِ فَقَالَ أَمَا لَوْ لَمْ تَفْعَلْ لَلَفَحَتْكَ النَّارُ أَوْ لَمَسَّتْكَ النَّارُ  

when I was beating a servant of mine, I heard a voice behind me saying: know, Abu Mas’ud-Ibn al-Muthanna said: “twice”-that Allah has more power over you than you have over him. I turned round and saw that it was that it was the prophet (May peace be upon him). I said : Messenger of Allah! He is free for Allah’s sake. He said : If you had not done it, fire would have burned you or the fire would have touched you.  

فَسَمِعْتُ مِنْ خَلْفِي صَوْتًا اعْلَمْ أَبَا مَسْعُودٍ قَالَ ابْنُ الْمُثَنَّى مَرَّتَيْنِ لَلَّهُ أَقْدَرُ عَلَيْكَ مِنْكَ عَلَيْهِ فَالْتَفَتُّ فَإِذَا هُوَ النَّبِيُّ ﷺ فَقُلْتُ يَا رَسُولَ اللَّهِ هُوَ حُرٌّ لِوَجْهِ اللَّهِ قَالَ أَمَا إِنَّكَ لَوْ لَمْ تَفْعَلْ لَلَفَعَتْكَ النَّارُ أَوْ لَمَسَّتْكَ النَّارُ