15 “The leech has two daughters.
‘Give! Give!’ they cry.
“There are three things that are never satisfied,
four that never say, ‘Enough!’:
16 the grave, the barren womb,
land, which is never satisfied with water,
and fire, which never says, ‘Enough!’
The leech has an insatiable appetite, which it has passed on to its daughters. Because they lack temperance, they also lack fulfillment. But here we have not only two things to consider, but three and even four to observe. Let us learn not to imitate them, lest we join them in their dissatisfaction.
The grave always has room for more. It looks upon the living as the covetous look upon worldly things (cf. 27:20), continually devouring yet never having enough. The barren womb represents the envious, whose preoccupation with what they lack robs them of contentment. “Give me children, or else I die” said Rachel, though she had much to be grateful for, being more beautiful than her sister and the favorite of her husband.
Land is like the human heart, which must be cultivated to make the most of blessings from above. If care is not taken thorns and thistles spring up, but there is much potential for those who diligently attend to it. Fire alludes to the flames of lust, which can be extraordinarily destructive when out of control.