All the labour of man [is] for his mouth,.... For the food of his mouth, as the Targum; for the sustenance of his body, for food and clothing, part being put for the whole: all that a man labours for is to get this; and if he does not enjoy it, his labour is in vain; meats are for the belly, which are taken in by the mouth, and for these a man labours; and if he does not eat them, when he has got them, he labours to no purpose;and yet the appetite is not filled; even the bodily or sensual appetite; no, not even by those who eat the fruit of their labour; for though their hunger is allayed for the present, and the appetite is satisfied for a while, yet it returns again, and requires more food, and so continually: or, "the soul is not filled", or "satisfied" ; it is the body only that is filled or satisfied with such things, at best; the mind of man grasps after greater things, and can find no contentment or satisfaction in earthly or sensual enjoyments.
This seems to be a new argument, proving the vanity of riches, from the narrow use of them; which only reaches to the body, not to the soul.