Sahih Bukhari
Manumission of Slaves
Volume: 003 / Book Number: 046 / Hadith Number: 732
Narrated Abu Huraira:
The Prophet said, "When your servant brings your meals to you then if he does not let him sit and share the meals, then he should at least give him a mouthful or two mouthfuls of that meal or a meal or two meals, as he has prepared it."