Charles Ellicott Commentary Isaiah 30:33

"For a Topheth is prepared of old; yea, for the king it is made ready; he hath made it deep and large; the pile thereof is fire and much wood; the breath of Jehovah, like a stream of brimstone, doth kindle it." — Isaiah 30:33 (ASV)

Tophet is ordained of old. —Literally, the Tophet, or place of burning, with perhaps the secondary sense of “a place of loathing.” Tophet was the name given to the Valley of Hinnom, outside Jerusalem, where, within living memory, Ahaz had made his son to pass through the fire to Moloch (2 Kings 16:3), and where similar sacrifices had taken place until Hezekiah’s accession. “The king” is, of course, the king of Assyria; but the Hebrew, “for the melek,” suggests a sarcastic reference to the god worshipped there, as if it were “for Moloch.” There was to be a great sacrifice of the Melek to the Moloch, who was like a mighty king (the name of the Ammonite god being a dialectic form of the Hebrew Melek), exulting in his victims. (Compare for the idea Isaiah 31:9).

The pile thereof is fire and much wood. —The word seems partly literal and partly figurative. The king of Assyria, though he did not die at Jerusalem, is represented as burned with stately ceremony in Tophet. Probably, as a matter of fact, it was the burial place of the corpses that were lying around the city after the pestilence had destroyed the Assyrian army, and they were literally burned there. For such a Moloch funeral, making the Valley of Hinnom then, as it afterwards became, a fitting type of Gehenna, a trench deep and wide and a mighty pyre were needed. Compare Jeremiah 19:12, where similar words are spoken of Jerusalem.