Musnad Ahmad 30:3136

Surayj narrated to us, he said: Fulayh narrated to us, from Ayyub ibn Abd al-Rahman ibn Sa'sa'ah al-Ansari, from Ya'qub ibn Abi Ya'qub, from Abu Hurayrah, he said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "A man shall not make a man stand up from his sitting place, but make space, and Allah will make space for you." "And if the servant of one of you prepares food, and he has attended to its heat and its hardship, then let him invite him to eat with him; and if he does not invite him, then let him hand him a portion of it." "And whoever sells a *musarrah* (an animal whose milk has been withheld in the udder to deceive the buyer), the buyer has the choice for three days; if he wishes, he may return it, and return with it a *sa'* of dates."