Abu 'Umar Zadhan said, "We were with Ibn 'Umar when he summoned a slave of his whom he had beaten and he uncovered his back. 'Does it hurt?' he asked. 'No,' he replied. Then he set him free. He picked up a stick from the ground and then said, 'I do not have a reward (for him) worth as much as this stick.' I asked, 'Abu 'Abdu'r-Rahman, why do you say this?' He replied, 'I heard the Prophet ﷺ say, "The expiation of someone who beats a slave more than he deserves or slaps his face is that he must set him free."'"

عَنْ ظَهْرِهِ فَقَالَ أَيُوجِعُكَ؟ قَالَ لاَ فَأَعْتَقَهُ ثُمَّ رَفَعَ عُودًا مِنَ الأَرْضِ فَقَالَ مَالِي فِيهِ مِنَ الأَجْرِ مَا يَزِنُ هَذَا الْعُودَ فَقُلْتُ يَا أَبَا عَبْدِ الرَّحْمَنِ لِمَ تَقُولُ هَذَا؟ قَالَ سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ أَوْ قَالَ مَنْ ضَرَبَ مَمْلُوكَهُ حَدًّا لَمْ يَأْتِهِ أَوْ لَطَمَ وَجْهَهُ فَكَفَّارَتُهُ أَنْ يُعْتِقَهُ