15 The leech has two suckers that cry out, "More, more!" There are three things that are never satisfied- no, four that never say, "Enough!": 16 the grave, the barren womb, the thirsty desert, the blazing fire.
Cruelty and covetousness are two daughters of the horseleech, that still cry, "Give, give," and they are continually uneasy to themselves. Four things never are satisfied, to which these devourers are compared. Those are never rich that are always coveting. And many who have come to a bad end, have owned that their wicked courses began by despising their parents' authority.
Matthew Henry's Commentary on Proverbs 30:15-16
Commentary on Proverbs 30:15-17
(Read Proverbs 30:15-17)
Cruelty and covetousness are two daughters of the horseleech, that still cry, "Give, give," and they are continually uneasy to themselves. Four things never are satisfied, to which these devourers are compared. Those are never rich that are always coveting. And many who have come to a bad end, have owned that their wicked courses began by despising their parents' authority.