Sahih Muslim Book 27, Hadith 63
It is essential to feed the slave, clothe him (properly) and not burden him with work which is beyond his power.
I saw Abu Dharr wearing clothes, and his slave wearing similar ones. I asked him about it, and he narrated that he had abused a person during the lifetime of Allah's Messenger (may peace be upoe. him) and he reproached him for his mother. That person came to Allah's Apostle (ﷺ) and made mention of that to him. Thereupon Allah's Apostle (ﷺ) said: You are a person who has (remnants of) Ignorance in him. Your slaves are brothers of yours. Allah has placed them in your hand, and he who has his brother under him, he should feed him with what he eats, and dress him with what he dresses himself, and do not burden them beyond their capacities, and if you burden them, (beyond their capacities), then help them.
When the slave of anyone amongst you prepares food for him and he serves him after having sat close to (and undergoing the hardship of) heat and smoke, he should make him (the slave) sit along with him and make him eat (along with him), and if the food seems to run short, then he should spare some portion for him (from his own share) - (another narrator) Dawud said:" i. e. a morsel or two". 4097