The prophecy was relayed during the reign of Uziyahu and relates to the sins of his era. Yeshayahu warned the people of the future devastation slated to befall their land if they did not change their ways.
Chronology of Sefer Yeshayahu – This approach assumes that the Book of Yeshayahu was written in chronological order.1 Since the heading of Chapter 6 reads, "בִּשְׁנַת מוֹת הַמֶּלֶךְ עֻזִּיָּהוּ", it assumes that the previous chapters occurred during Uziyahu's reign. This creates a difficulty, as it is hard to understand the need for a special mission resembling an initiation prophecy in chapter 6. Therefore, R. Eliezer of Beaugency suggests that a lot of time passed between prophesying chapters 1-5 and 6.
Relationship to time period
Description of sin – The interpersonal sins portrayed seem to somewhat match what Amos rebukes the nation about. Though we do not know much about their spiritual situation during Uziyahu's reign, other than that they continued to sacrifice on outside alters. Uziyahu himself is depicted as a good king who followed in Amazyahu's path; besides that he got leprosy, which according to Divrei HaYamim II 26:16 was because "גָּבַהּ לִבּוֹ עַד לְהַשְׁחִית וַיִּמְעַל בַּי"י אֱלֹהָיו". This does not seem to fully match the portrait Yeshayahu paints of "עָזְבוּ אֶת י"י".
Description of destruction – R. Eliezer of Beaugency reads the description of destruction to be speaking of the future,2 Sancheriv's rise on Chizkiyahu and the capturing of the fortified cities of Yehuda described in Melakhim II 18:13.3 "וְנוֹתְרָה בַת צִיּוֹן כְּסֻכָּה בְכָרֶם" describes the besiegement of Yerushalayim, which was almost the only city left not captured. "אַרְצְכֶם שְׁמָמָה" can relate to the way the whole country will look after the ten tribes exile to Ashur.
Description of consolation – R. Eliezer of Beaugency seems to read the verses of נחמה to be during the time of "אַחֲרִית הַיָּמִים" mentioned in the next chapter (2:2), which he does not explicate when it is.4 "אֲשֶׁר חָזָה" in 2:1 regards the prophecy told right beforehand.
"עַל מֶה תֻכּוּ עוֹד תּוֹסִיפוּ סָרָה" – This verse is a bit hard for R. Eliezer of Beaugency to explain, because it states almost explicitly that the nation was afflicted in the past, and he reads the description of destruction as talking about the future. Therefore he suggests Yeshayahu is talking about the afflictions from the beginning of the time of the judges until now, which have not affected the nation's actions.
During Achaz's Reign
Yeshayahu's words were directed at Achaz and his generation. He decried their sins, and highlighted the resulting destruction that had been wrought on the land in the hopes of encouraging the people to change their ways
Chronology of Sefer Yeshayahu – Not in chronological order
Relationship to time period
Description of sin – The description of the sin of idolatry matches Achaz's time period. Shadal questions this approach, however, because the focus of the verses seems to be more on the interpersonal sins, as the verses do describe that sacrifices were brought to Hashem just for the wrong purpose. The only explicit hint that they worshiped idols which certainly was the central sin in the time of Achaz, are the words "כִּי יֵבֹשׁוּ מֵאֵילִים אֲשֶׁר חֲמַדְתֶּם" (in verse 29).
Description of destruction – These verses can be read about the present, the desolation that resulted from the battles Achaz fought and lost against Aram, Pekach, Pelishtim, and Ashur.
Description of consolation
During Chizkiyahu's Reign
Yeshayahu delivered this prophecy during the reign of Chizkiyahu. This approach divides regarding both the specific period referred to and the sins being rebuked:
After Chizkiyahu's Religious Reform
After Chizkiyahu brought the nation back to Hashem, they continued to sin in the interpersonal sphere and it is about this which Yeshayahu prophesied.
Chronology of Sefer Yeshayahu – Shadal explains this prophecy is first even though chronologically it belongs later, because of the importance of the rebuke which includes major ethics and believing in Hashem. He adds that chapter 1 is the first prophecy Yeshayahu received, but not the first to be relayed to the nation (it was only relayed during Chizkiyahu's reign).
Relationship to time period
Description of sin – This approach reads the verses describing the sin of idolatry, as focusing on the interpersonal issues during Chizkiyahu's time. Chizkiyahu worked to restore the worship of Hashem, but not the justice.
Verses that argue for a sin of idolatry: – This approach must reread verses which rebuke of the sin of idolatry which was not the main sin during Chizkiyahu's time:
"וְהֵם פָּשְׁעוּ בִי" (2-4) – The nation did not follow Hashem's path of doing justice and righteousness, and acted unjustly.
"כִּי יֵבֹשׁוּ מֵאֵילִים אֲשֶׁר חֲמַדְתֶּם" (29-31) – According to Shadal, these words of "מֵאֵילִים" and "מֵהַגַּנּוֹת" refer to trees parallel to ministers and kings, who the rogue judges relied on. The judges will be ashamed of the tall trees that appointed them and whom they trusted and sat in their shade to allow them to do injustice and violence. On the other hand, Hoil Moshe explains more literally, of the sexual crimes done under trees.
Description of destruction – Shadal also reads it in the present, but describing the destruction left from the time of Achaz from the battles he fought and lost against Aram, Pekach, Edom, and Pelishtim. Shadal notes a parallel description to Divrei HaYamim II 29:9 where Chizkiyahu says, "וְהִנֵּה נָפְלוּ אֲבוֹתֵינוּ בֶּחָרֶב וּבָנֵינוּ וּבְנוֹתֵינוּ וְנָשֵׁינוּ בַּשְּׁבִי עַל זֹאת".
Description of consolation
After the exile of the ten tribes
Yeshayahu rebuked the people for both their sins of idolatry and their crimes against their fellow men, bemoaning that they learned nothing from the exile of the ten tribes.
Chronology of Sefer Yeshayahu – Rashi says explicitly that chapter one is out of chronological order, as chapter six recounts Yeshayahu's call to prophecy and this chapter was said afterwords. He proves from the language of "אֲשֶׁר חָזָה עַל יְהוּדָה וִירוּשָׁלִָם" which is not inclusive of all the visions regarding other nations, so it must be an introduction just for the chapter and not for the book.6 He does not explain why it is in non-chronological order.
Relationship to time period – Yeshayahu is talking to the tribe of Yehuda so they will learn from the overthrow of the kingdom of Yisrael, to do good virtues.
Description of sin – Rashi can posit like Shadal above, that the focus of the rebuke was on the sins between man and fellow man, specifically the injustice in the country, occurring during the time of Chizkiyahu.
Description of destruction – Rashi reads these verses to be talking of the present desolation, resulting from the exile of most of the population. At the time Yeshayahu is talking, the land is desolated. Shadal notes a difficulty that one would have assumes the prophecy would mention somewhere at least incidentally the fact that the ten tribes exiled to Ashur, as it is the grounds for the whole prophecy.7
Description of consolation – R. Yosef Kara suggests the consolation refers to the returning of the exiled from exile.
"עַל מֶה תֻכּוּ עוֹד תּוֹסִיפוּ סָרָה" – R. Yosef Kara reads this verse, that Hashem is saying He exiled the ten tribes to no avail, because the people left in the country didn't learn virtues rather just continued to transgress.
During All Four Kings
Yeshayahu relayed this prophecy multiple times, during the reigns of each of Uziyahu, Yotam, Achaz, and Chizkiyahu, as it pertained to all of them.
Chronology of Sefer Yeshayahu – Abarbanel suggests the reason this prophecy is first, is because it was repeated so many times during the reign of each of the four kings, or because it was the first prophecy Yeshayahu prophesied during Uziyahu's reign.
Relationship to time period – Abarbanel understands Yeshayahu is warning the tribe of Yehuda of the destruction to come on the rest of the tribes and is telling them to do better so it won't happen to them like will happen to the rest of the tribes.
Description of sin – Radak notes that the representation of the sins of the people matches all of the four kings.8 Shadal asks how can one say the same prophecy for a different situation, since the sin of the people is different in each time period. Additionally, he questions that the main focus in the chapter is not about worshiping idols, and it even sounds like the people were bringing sacrifices to the temple.
Description of destruction – Radak says the verses are referring to the fortified cities the king of Ashur captured in the time of Chizkiyahu. Abarbanel presents both options that these verses should be read as talking about the exile of the ten tribes, either in the present, or in the future.
Description of consolation – Radak seems to say the consolation will happen during the Messianic era, besides for verse 29 which talks about the elimination of idolatry which occurred in the destruction of the Temple.