Sahih Muslim
The Book of Oaths (Kitab Al-Aiman)
Book Number: 015 / Hadith Number: 4096
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: 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