Hilal b. Yasaf said :

We were staying in the house of Suwaid b. Muqarrin. There was among us an old man who was hot-tempered. He had a slave-girl with him. He gave a slap on her face. I never saw Suwaid more angry than on that day. He said: there is no alternative for you except to free her. I was the seventh child in order of Muqarrin and we had only a female servant. The youngest of us gave a slap on her face. The prophet (ﷺ) commanded us to set her free.

حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا فُضَيْلُ بْنُ عِيَاضٍ، عَنْ حُصَيْنٍ، عَنْ هِلاَلِ بْنِ يِسَافٍ، قَالَ كُنَّا نُزُولاً فِي دَارِ سُوَيْدِ بْنِ مُقَرِّنٍ وَفِينَا شَيْخٌ فِيهِ حِدَّةٌ وَمَعَهُ جَارِيَةٌ فَلَطَمَ وَجْهَهَا فَمَا رَأَيْتُ سُوَيْدًا أَشَدَّ غَضَبًا مِنْهُ ذَاكَ الْيَوْمَ قَالَ عَجَزَ عَلَيْكَ إِلاَّ حُرُّ وَجْهِهَا لَقَدْ رَأَيْتُنَا سَابِعَ سَبْعَةٍ مِنْ وَلَدِ مُقَرِّنٍ وَمَا لَنَا إِلاَّ خَادِمٌ فَلَطَمَ أَصْغَرُنَا وَجْهَهَا فَأَمَرَنَا النَّبِيُّ صلى الله عليه وسلم بِعِتْقِهَا ‏.‏