Charles Ellicott Commentary Isaiah 57:9

"And thou wentest to the king with oil, and didst increase thy perfumes, and didst send thine ambassadors far off, and didst debase thyself even unto Sheol." — Isaiah 57:9 (ASV)

You went to the king ... —The alteration of a single letter would give to Molech; and this may be the meaning even of the text as it stands. Looking to the Manasseh-surroundings of the passage, however, it is more natural to refer the words to the king, the great king of Assyria, whose religion Judah had basely and shamefully adopted. The sin of Ahaz (2 Kings 16:11) had been reproduced by his grandson. The description that follows is that of a harlot adorning herself for her evil calling, and finds its best illustration in Proverbs 7:14-17.

Looking to the previous traces of Isaiah’s study of that book (Isaiah 11:1–4, and so on), we may, perhaps, find in it a deliberate reproduction of that passage. The ointment and perfumes are symbols of the treasures which were lavished to secure the Assyrian alliance. The words help us to understand Isaiah’s indignation at what must have seemed to him the initial step of a similar policy on the part of Hezekiah (Isaiah 39:3–7). The words which point to the far-off land, to which the messengers were sent, seem almost like an echo from that king’s apology.

Even unto hell —i.e., Hades or Sheol, the world of the dead—as the symbol of an abysmal depth of degradation.