We can describe how people know the one true God in three basic ways. First, all people know Him as Creator. He has made the world from nothing, and He reveals Himself in the world such that all people have at least some awareness of His attributes and hence some knowledge that He is the Lord of glory (Ps. 19; Rom. 1:18–32). Second, those who trust in Christ alone for salvation know the one true God as Savior. They, as undeserving sinners, know His mercy in redeeming them, and through that knowledge have a better understanding of His glory (Rom. 9:22–24). Finally, impenitent sinners know God not as Savior but only as Judge. Try as they might to deny it, they know their sin and that a day of judgment is coming (Rom. 2:1–16). And on that day of judgment, today’s passage tells us, all people will see God’s glory manifested in His final judgment on wickedness.
Isaiah proclaims the coming day on which the “Lord will enter into judgment . . . with all flesh” (Isa. 66:15–16). On that day, nothing will escape God’s sight, for He knows the “works” and “thoughts” of all people (v. 18). And on that day, mere ritual observance or outward religiosity will save no one, for God will bring an end to the wicked, both those who make an outward show of faith and those who reject His covenant outright (v. 17).
Yet that will not be a grim day for all people. For those who know Christ, it will be a day of salvation, as God has already pronounced judgment on His people: He has declared them righteous on account of the imputed righteousness of Christ (Rom. 5:1–2; 2 Cor. 5:21). Thus, many nations will come to God in Christ and be received as priests unto Him, as those who have been granted the right to be in His holy presence unafraid. All others, those who are not in Christ by faith alone, will at that point receive judgment, and it will be a judgment of condemnation (Isa. 66:18–24).
On that day, God will manifest His glory. All nations will see it (v. 18), and it will be heralded by all (v. 19). For the Creator gets glory not only in creating and saving people, but also in executing His righteous judgment. That day of judgment will magnify the Lord’s glory, for we will see His attribute of righteousness on full display, and every mouth will be stopped and unable to protest divine injustice, for it will be plainly evident under God’s law that there is not injustice at all in our Lord (Rom. 3:19). God will show His glory in the end.