The prodigious chossid, Rabbi Yitzchak the masmid, would often quote the Talmud’s dictum in reference to one’s service of G-d:
“If a slave’s [work] is not worth the food he eats, what do his master and mistress want him for!?” If the slave does not even produce enough to cover his basic maintenance he is of no use to his master.
The same too is in our service of G-d. We need to be worth something and do something for our creator. If not—then what is the whole point?!
 Gitin, 12a