Sahih Muslim 1662
Sahih Muslim · Book 27: The Book of Oaths · Feeding a slave what one eats and clothing him as one clothes oneself, and not burdening him with more than he bear
Abu Huraira reported Allah's Messenger (ﷺ) as saying:
وَحَدَّثَنِي أَبُو الطَّاهِرِ، أَحْمَدُ بْنُ عَمْرِو بْنِ سَرْحٍ أَخْبَرَنَا ابْنُ وَهْبٍ ، أَخْبَرَنَا عَمْرُو، بْنُ الْحَارِثِ أَنَّ بُكَيْرَ بْنَ الأَشَجِّ ، حَدَّثَهُ عَنِ الْعَجْلاَنِ ، مَوْلَى فَاطِمَةَ عَنْ أَبِي هُرَيْرَةَ ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم أَنَّهُ قَالَ " لِلْمَمْلُوكِ طَعَامُهُ وَكِسْوَتُهُ وَلاَ يُكَلَّفُ مِنَ الْعَمَلِ إِلاَّ مَا يُطِيقُ " .
It is essential to feed the slave, clothe him (properly) and not burden him with work which is beyond his power.