Regarding the rights of slaves
حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا يَحْيَى، عَنْ سُفْيَانَ، قَالَ حَدَّثَنِي سَلَمَةُ بْنُ كُهَيْلٍ، قَالَ حَدَّثَنِي مُعَاوِيَةُ بْنُ سُوَيْدِ بْنِ مُقَرِّنٍ، قَالَ لَطَمْتُ مَوْلًى لَنَا فَدَعَاهُ أَبِي وَدَعَانِي فَقَالَ اقْتَصَّ مِنْهُ فَإِنَّا مَعْشَرَ بَنِي مُقَرِّنٍ كُنَّا سَبْعَةً عَلَى عَهْدِ النَّبِيِّ صلى الله عليه وسلم وَلَيْسَ لَنَا إِلاَّ خَادِمٌ . فَلَطَمَهَا رَجُلٌ مِنَّا فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أَعْتِقُوهَا " . قَالُوا إِنَّهُ لَيْسَ لَنَا خَادِمٌ غَيْرَهَا . قَالَ " فَلْتَخْدُمْهُمْ حَتَّى يَسْتَغْنُوا فَإِذَا اسْتَغْنَوْا فَلْيُعْتِقُوهَا " .
Narrated Mu'awiyah ibn Suwayd ibn Muqarrin: I slapped a freed slave of ours. My father called him and me and said: Take retaliation on him. We, the people of Banu Muqarrin, were seven during the time of the Prophet (ﷺ),and we had only a female servant. A man of us slapped her. The Messenger of Allah (ﷺ) said: Set her free. They said: We have no other servant than her. He said: She must serve them till they become well off. When they become well off, they should set her free.