By c. 740 BC the wickedness of Judah, particularly its political and religious center in Jerusalem, had become unbearable for the Lord. When God looked at his people what he saw was not the child he had raised to walk in his ways, but a rebellious and wayward son (Isaiah 1:2-3). They were sick, infected with a disease that spreads more quickly than any other and with more devastating effects, (i.e., sin) (1:5-6). Their religious and moral life had deviated from the ways of the Lord so much that he referred to them as "rulers of Sodom" and "people of Gomorrah" (1:10). The problem wasn't their lack of religious observance, they kept that up just fine and it had become unbearable to the God who ordained those sacrifices and festivals (1:11-16). At issue was the blood of the innocent and helpless on their hands; what God desired was their pursuit of justice (1:1-17). In what can only be seen as a public "dressing down" of his people, God offers the promise that their sins can be cleansed (1:18). If they will return to him by becoming obedient they will receive his blessing, but otherwise they can only expect destruction (1:19).
Yet even this destruction is redemptive. As the image below shows, Isaiah 1:21-26 (NIV, 1984) lays out the situation as God's sees it, his plan to "purify" them, and his ultimate purpose in this work.
The passage centers on verse 24-25a and God's vengeance on his enemies—his people! He will right every wrong, and true justice will reign. In this way God brings genuine restoration and renewal so that righteousness and faithfulness become the very identity of those who are unrighteous and unfaithful.
In a generation marked by unrighteousness and unfaithfulness even in the church, we would do well to thank God for his purifying work. Judgment on the church is not for our destruction, but for our sanctification.
"Yet if anyone suffers as a Christian, let him not be ashamed, but let him glorify God in that name. For it is time for judgment to begin at the household of God" (1 Pet 5:16-17).