Albert Barnes Commentary Proverbs 30:15-16

"The horseleach hath two daughters, [crying], Give, give. There are three things that are never satisfied, [Yea], four that say not, Enough: Sheol; and the barren womb; The earth that is not satisfied with water; And the fire that saith not, Enough." — Proverbs 30:15-16 (ASV)

Note the numeration mounting to a climax, the two, the three, the four (Amos 1:3 and following). The word rendered “horseleach” is found nowhere else, and its etymology is doubtful; however, there are good grounds for taking the word in its literal sense, as giving an example in the natural world of the insatiable greed of which the next verse gives other instances. Its voracious appetite is here represented, to express its intensity, as two daughters, uttering the same ceaseless cry for more.

(Proverbs 30:16) The grave - Hebrew שׁאול sh^e'ôl. The “Hell” or Hades of (Proverbs 27:20), all-consuming yet never full.