Mu'awiya ibn Muqarrin said, "I slapped a mawla of mine and he fled. Then my father called me and said, 'I will tell you a story. We, the sons of Muqarrin, were seven, and we had one servant. Then one of us slapped her and that was mentioned to the Messenger of Allah, may Allah bless him and grant him peace. He said, 'Order them to set her free.' The Prophet, may Allah bless him and grant him peace, was told. 'She is the only servant they have.' He said, 'Then let them hire her and when they no longer need her, let her go on her way.'"
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُسَدَّدٌ، قَالَ: حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ سُفْيَانَ قَالَ: حَدَّثَنِي سَلَمَةُ بْنُ كُهَيْلٍ قَالَ: حَدَّثَنِي مُعَاوِيَةُ بْنُ سُوَيْدِ بْنِ مُقَرِّنٍ قَالَ: لَطَمْتُ مَوْلًى لَنَا فَفَرَّ، فَدَعَانِي أَبِي فَقَالَ لَهُ: اقْتَصَّ، كُنَّا وَلَدَ مُقَرِّنٍ سَبْعَةً، لَنَا خَادِمٌ، فَلَطَمَهَا أَحَدُنَا، فَذُكِرَ ذَلِكَ لِلنَّبِيِّ صلى الله عليه وسلم فَقَالَ: مُرْهُمْ فَلْيُعْتِقُوهَا، فَقِيلَ لِلنَّبِيِّ صلى الله عليه وسلم: لَيْسَ لَهُمْ خَادِمٌ غَيْرَهَا، قَالَ: فَلْيَسْتَخْدِمُوهَا فَإِذَا اسْتَغْنَوْا خَلُّوا سَبِيلَهَا.
sunnah.com