THE OPENING VERSE OF ISAIAH 1 introduces the massive sweep of the book. It announces a vision that Isaiah saw, a vision that runs through the reigns of the four kings of Judah from King Uzziah on.
The first section (Isa. 1:2-9) displays how far the nation has fallen. God himself raised up the nation of Israel (Isa. 1:2)---indeed, he "reared" them, brought them up like children; and like rebellious children they have turned against him. An ox or a donkey knows more of its true home than Israel knows of hers. The heavens and earth are invited to listen in on the rebuke (Isa. 1:2), both as a measure of the intensity of the rebellion and because there is a sense in which the well-being of the entire universe depends on whether God's people obey or disobey his word. The description of the devastation in the land (Isa. 1:5-9) is not metaphorical: probably what is being described is the bloody carnage that accompanied the invasion of Judah by Sennacherib's Assyrian forces (701 B.C.)---a foretaste of judgment to come.
From here to the end of the chapter, the thought runs in three movements:
(1) Israel is excoriated for her corrupt and hypocritical worship (Isa. 1:10-17). In dripping sarcasm, God addresses his covenant people as Sodom and Gomorrah. They maintain the stipulated sacrificial system and high feast days, but God insists he cannot bear their "evil assemblies" (Isa. 1:13); he hates them (Isa. 1:14). God will not even listen to his people when they pray (Isa. 1:15), for oppression of the weak and corruption in the administration have reached such proportions that he must act in line with the Sinai covenant (Deut. 21:18-21). He can ignore these violations no longer.
(2) Nevertheless Israel is still being invited to forgiveness and cleansing: " 'Come now, let us reason together,' says the LORD. 'Though your sins are like scarlet, they shall be as white as snow; though they are red as crimson, they shall be like wool' " (Isa. 1:18-20). It is not cultic observance that triggers such forgiveness, but repentance: "If you are willing and obedient, you will eat the best from the land" (Isa. 1:19). The alternative is judgment (Isa. 1:20). Later in the book the basis for such forgiveness will be set forth; the devastating judgment of oppression and exile was not necessary, but so often we prefer sin to salvation, greed to grace.
(3) Yet Zion (representing the people of God) will one day "be redeemed with justice, her penitent ones with righteousness" (Isa. 1:27). There is no final redemption that ignores justice and righteousness; only judgment awaits the impenitent (Isa. 1:28, 31).