I have caused you pain. He said: No. But he (Ibn Umar) said: You are free. He then took hold of something from the earth and said: There is no reward for me even to the weight equal to it. I heard Messenger of Allah ﷺ as saying: He who beats a slave without cognizable offence of his or slaps him (without any serious fault), then expiation for it is that he should set him free.  

مَا لِي فِيهِ مِنَ الأَجْرِ مَا يَزِنُ هَذَا إِنِّي سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ مَنْ ضَرَبَ غُلاَمًا لَهُ حَدًّا لَمْ يَأْتِهِ أَوْ لَطَمَهُ فَإِنَّ كَفَّارَتَهُ أَنْ يُعْتِقَهُ  

[Machine] I heard the Messenger of Allah ﷺ saying, "Whosoever strikes his servant, causing them pain or slaps them, their expiation is to set them free."  

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ مَنْ ضَرَبَ غُلَامًا لَهُ حَدًّا لَمْ يَأْتِهِ أَوْ لَطَمَهُ فَإِنَّ كَفَّارَتَهُ أَنْ يُعْتِقَهُ  

[Machine] The Prophet ﷺ said, "Whoever strikes his servant and does not free him, his expiation is to free him."  

عَنِ النَّبِيِّ ﷺ قَالَ «مَنْ ضَرَبَ عَبْدَهُ حَدًّا لَمْ يَأْتِهِ فَكَفَّارَتُهُ عِتْقُهُ»