I seek refuge with Allah, but he continued beating him, whereupon he said: I seek refuge with Messenger of Allah, and he spared him. Thereupon Messenger of Allah ﷺ said: By Allah, God has more dominance over you than you have over him (the slave). He said that he set him free.
أَنَّهُ كَانَ يَضْرِبُ غُلاَمَهُ فَجَعَلَ يَقُولُ أَعُوذُ بِاللَّهِ قَالَ فَجَعَلَ يَضْرِبُهُ فَقَالَ أَعُوذُ بِرَسُولِ اللَّهِ فَتَرَكَهُ فَقَالَ رَسُولُ اللَّهِ ﷺ وَاللَّهِ لَلَّهُ أَقْدَرُ عَلَيْكَ مِنْكَ عَلَيْهِ قَالَ فَأَعْتَقَهُ