Isa 66:1-24 explains that though the worship of God is violated now, in the future falsehood and hypocrisy will be judged, true worship will spread, and God will be honored forever. True worship will last forever.
God Hates Religious Hypocrisy (Isa 66:1-6)
God is greater than the institutions he has authorized (Isa 66:1), and he will never be manipulated by them. Yet God looks with favor on "those who are humble and contrite in spirit, and who tremble at (his) word" (Isa 66:2). God despises proper outward worship without a trembling heart before him; it's as bad as outright sin (Isa 66:3,4). Such false worshipers self-righteously despise true worshipers (Isa 66:5). God will judge and repay them as they deserve (Isa 66:6).
The Certainty of Future Blessing (Isa 66:7-14)
Our doubts cause us to fear that God will not prove faithful to all his promises to his helpless people (Isa 66:7-9). But the certainty of future blessing calls for joy in the present (Isa 66:10-14); this underscores the comfort proclaimed to his people who were exiled in Babylon (Isa 40:1).
Fiery Judgment Contrasts God's Declaration of His Glory Worldwide (Isa 66:15-17; 18-24)
Eternal punishment via the final judgment by fire is promised to the religious hypocrites and the rebellious (Isa 66:15-17), while the time will come for God to declare his own glory through his chosen faithful remnant (Isa 66:18-20), and the "unclean" Gentiles will carry out the calling of "holy" Israel (Isa 66:21). Despite his people's rebellion and sins (Isa 1:2,3), God would renew the endless worship of his new people (Isa 66:23,23). God's final unending judgment is a sharp and terrifying contrast to the apparent success of the wicked in this present life. Yet it is a comforting assurance that God will judge the wicked and wickedness forever (Isa 66:24).
Practical Application: The gospel is good news to the contrite but bad news to the hypocrites and the rebellious.
How should one live?: With a humble contrite heart that trembles at God's word (Isa 66:2).
What's next? Zephaniah 1:1-3:20.