isaiah 57:9 And thou wentest to the king with ointment, and didst increase thy perfumes, and didst send thy messengers far off, and didst debase thyself even unto hell. - Free Bible Online

      9. the king--the idol which they came to worship, perfumed with oil, like harlots (Jer 4:30; Eze 23:16, 40). So "king" means idol (Am 5:26; Zep 1:5); (malcham meaning "king") [ROSENMULLER]. Rather, the king of Assyria or Egypt, and other foreign princes, on whom Israel relied, instead of on God; the "ointment" will thus refer to the presents (Ho 12:1), and perhaps the compliances with foreigners' idolatries, whereby Israel sought to gain their favor [LOWTH] (Isa 30:6; Eze 16:33; 23:16; Ho 7:11).
      send . . . messengers far off--not merely to neighboring nations, but to those "far off," in search of new idols, or else alliances.
      even unto hell--the lowest possible degradation.

JFB.