 Rabbi Eleazar deduced from "The appetite of a laborer labors for him, for his mouth craves it of him," that Scripture means that people are born to toil by mouth – that is, study – rather than toil by hand.And Rabbi Eleazar deduced from "This book of the Torah shall not depart out of your mouth, but you shall meditate therein day and night, that you may observe to do according to all that is written therein," that people were born to work in the Torah rather than in secular conversation.And this coincides with Rava's dictum that all human bodies are receptacles; happy are they who are worthy of being receptacles of the Torah.