After the devastation of the first six of the trumpets, the people of the earth do not repent of their idolatry (Revelation 9:20-21). This description of idolatry is consistent with the Old Testament, idols are things crafted by men that cannot do anything (Ps 115:5-7; 1 Cor 10:20). Standing on the foundation of texts like Deuteronomy 32:17, Revelation 9:20 says the worship of idols is the worship of demons. This is certainly the same view of idolatry as other Second Temple Jewish literature:
1 Enoch 99.6–7 “Again I swear to you, you sinners, for sin has been prepared for the day of unceasing blood. 7 (And those) who worship stones, and those who carve images of gold and of silver and of wood and of clay, and those who worship evil spirits and demons, and all kinds of idols not according to knowledge, they shall get no manner of help in them.
Testament of Judah 23.1 “My grief is great, my children, on account of the licentiousness and witchcraft and idolatry that you practice contrary to the kingship, following ventriloquists, omen dispensers, and demons of deceit.
The people of the earth do not repent of any of their offenses: murders, magic arts, sexual immorality, and thefts.” Three of these four are in the ten commandments (murder, adultery, and theft). The fourth, “magical arts” is sometimes translated “sorcery” (φάρμακον). Although this particular offense seems out of place alongside three of the Ten Commandments, the related φάρμακος describes the Egyptian magicians in the Septuagint (Exod 7:11; 9:11). Sorcerers or magicians are among those consigned to the Lake of Fire in Revelation 21:8 and 22:15.
The Old Testament often associated sorcery and idolatry. For example, 2 Kings 9:22, Jehu says there can be no peace in Israel because of the many “the whorings and the sorceries of your mother Jezebel.” Magicians are associated with sexual immorality in some Second Temple literature. For example, in the Testament of Reuben 4.9 Egyptian woman used magicians and potions for him to entrap Joseph sexually.
In the Temple Scroll idolatry and magic are abominations which will result in exile:
11Q19 Col. lx:17-20 Among you there should not be found anyone who makes his son or his daughter pass 18 through fire, anyone who practices divination, astrologers, sorcerers, wizards, anyone who performs incantations, anyone who consults a spirit 19 or oracles or anyone who questions the dead; because all those who do these things are an abomination to me. 20 And owing to these abominations I shall dispossess them before you.
I suggest the immediate context of idolatry and sexual immorality is participation in festivals and banquets honoring Roman gods, perhaps even the imperial cult. The letters to the seven churches often warned believers to repent (2:5 (2x); 2:16; 2:21, 22; 3:3; 3:19). In the case of Thyatira (2:18-28), the use of Jezebel clearly associates idolatry and immorality, as in 2 Kings 9:22, “the whorings and the sorceries of your mother Jezebel.”
That the people of the earth refuse to repent after the sixth trumpet is consistent with the sixth seal. Rather than repent, the people of the earth call on the rocks and mountains to hide them from the wrath of the Lamb. Greg Beale draws a parallel to the conclusion of the plagues in Egypt, God hardened the heart of Pharaoh (Revelation, 517). He argues there is a “theological purpose” to these warnings, God is providing sufficient opportunities for repentance so that he may demonstrate his sovereignty and justice when he finally judges those who are not sealed by God when the seventh trumpet sounds (11:18).
Like the plagues on the Egyptians in Exodus, the plagues in Revelation 7-9 are not evangelistic. They are fair warnings by the sovereign God that final judgment is coming soon even if the ones who are warned are have no interested in repenting.