15 The night-spirit has two daughters, Give, give. There are three things which are never full, even four which never say, Enough: 16 The underworld, and the woman without a child; the earth which never has enough water, and the fire which never says, Enough.
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.