Difference between revisions of "Yeshayahu's Mission in Chapter 6/2"

From AlHaTorah.org
Jump to navigation Jump to search
m
m
Line 61: Line 61:
 
<opinion>Yeshayahu Resigned
 
<opinion>Yeshayahu Resigned
 
<p>When the nation refused to heed Yeshayahu's words and mocked the punishments he forewarned, Yeshayahu gave up and stopped rebuking the people.</p>
 
<p>When the nation refused to heed Yeshayahu's words and mocked the punishments he forewarned, Yeshayahu gave up and stopped rebuking the people.</p>
<point><b>Mocking of Yeshayahu</b> – This position points to <a href="Yeshayahu5-18-20_2" data-aht="source">Yeshayahu 5:18-20</a> as evidence that the nation did not believe in Yeshayahu's prophecies and assumed that they would not be punished for their deeds.<fn>Cf. Amos 5:18 which also speaks of the nation not believing in the punishment foretold by the prophet.&#160; Since Amos and Yeshayahu are prophesying at the same time, this is further evidence that the generation mocked its prophets.</fn> [There is no explicit evidence, however, that Yeshayahu therefore refrained from further chastisement.]</point>
+
<point><b>Mocking of Yeshayahu</b> – This position points to <a href="Yeshayahu5-18-20_2" data-aht="source">Yeshayahu 5:18-20</a> as evidence that the nation did not believe in Yeshayahu's prophecies and assumed that they would not be punished for their deeds.<fn>Cf. Amos 5:18 which also speaks of the nation not believing in the punishment foretold by the prophet.&#160; Since Amos and Yeshayahu are prophesying at the same time, this is further evidence that the generation mocked its prophets.</fn> [There is no explicit evidence in the verses, however, that Yeshayahu therefore refrained from further chastisement.]</point>
<point><b>Chronology</b> – This position can maintain chronological order in the book, as it does not view Chapter 6 as Yeshayahu's first prophecy.</point>
+
<point><b>Chronology of the book</b> – This position can maintain chronological order in the book, as it does not view Chapter 6 as Yeshayahu's first prophecy.</point>
 
<point><b>The vision</b> – Yeshayahu receives a grandiose vision of Hashem on His throne since this is a re-initiation into prophecy, and not merely a new message.</point>
 
<point><b>The vision</b> – Yeshayahu receives a grandiose vision of Hashem on His throne since this is a re-initiation into prophecy, and not merely a new message.</point>
 
<point><b>"וְהַבַּיִת יִמָּלֵא עָשָׁן"</b> – The smoke might be symbolic of Hashem's anger and disappointment in Yeshayahu for having abandoned his task.</point>
 
<point><b>"וְהַבַּיִת יִמָּלֵא עָשָׁן"</b> – The smoke might be symbolic of Hashem's anger and disappointment in Yeshayahu for having abandoned his task.</point>
<point><b>"אוֹי לִי כִי נִדְמֵיתִי"</b> – This position understands "נִדְמֵיתִי" to mean "I was silent". With Hashem's renewed revelation ("כִּי אֶת הַמֶּלֶךְ י"י צְבָאוֹת רָאוּ עֵינָי"), Yeshayahu was ashamed that he had decided to remain silent and had not continued to rebuke the people, despite their taunts ("עַם טְמֵא שְׂפָתַיִם").<fn>Yeshayahu notes that he should have realized that the people are "of impure lips" and not taken it personally.&#160; In not chastising them, he became one of them, an "אִישׁ טְמֵא שְׂפָתַיִם".</fn></point>
+
<point><b>"אוֹי לִי כִי נִדְמֵיתִי"</b> – This position understands "נִדְמֵיתִי" to mean "I was silent". With Hashem's renewed revelation ("כִּי אֶת הַמֶּלֶךְ י"י צְבָאוֹת רָאוּ עֵינָי"), Yeshayahu was ashamed that he had decided to remain silent and had not continued to rebuke the people despite their taunts ("עַם טְמֵא שְׂפָתַיִם").<fn>Yeshayahu notes that he should have realized that the people are "of impure lips" and not taken it personally.&#160; In not chastising them, he became one of them, an "אִישׁ טְמֵא שְׂפָתַיִם".</fn></point>
 
<point><b>"וְסָר עֲוֺנֶךָ"</b> – Hashem reassures Yeshayahu that he is forgiven and purges him of any guilt.</point>
 
<point><b>"וְסָר עֲוֺנֶךָ"</b> – Hashem reassures Yeshayahu that he is forgiven and purges him of any guilt.</point>
 
<point><b>"אֶת מִי אֶשְׁלַח... וָאֹמַר הִנְנִי שְׁלָחֵנִי"</b> – Hashem gives Yeshayahu the opportunity to prove that he is once again willing to prophesy by asking "אֶת מִי אֶשְׁלַח".&#160; Yeshayahu immediately replies in the positive, volunteering to embark on Hashem's mission.</point>
 
<point><b>"אֶת מִי אֶשְׁלַח... וָאֹמַר הִנְנִי שְׁלָחֵנִי"</b> – Hashem gives Yeshayahu the opportunity to prove that he is once again willing to prophesy by asking "אֶת מִי אֶשְׁלַח".&#160; Yeshayahu immediately replies in the positive, volunteering to embark on Hashem's mission.</point>
Line 75: Line 75:
 
<point><b>Punishment</b></point>
 
<point><b>Punishment</b></point>
 
<point><b>Biblical Parallels</b><ul>
 
<point><b>Biblical Parallels</b><ul>
<li>Eliyahu</li>
+
<li>Eliyahu – According to some opinions, Eliyahu's flight to Chorev marked his desire to stop prophesying.&#160; In its aftermath, he, too, receives an elaborate vision of Hashem in which he is re-inititaed into prophecy. For elaboration, see <a href="Eliyahu at Chorev" data-aht="page">Eliyahu at Chorev</a></li>
<li>Moshe</li>
+
<li>Moshe </li>
 
</ul></point>
 
</ul></point>
 
</opinion>
 
</opinion>
Line 93: Line 93:
 
<p>Since the people had not forsaken Hashem during the reign of Uziyahu, there was no need for chastisement for much of his rule.</p>
 
<p>Since the people had not forsaken Hashem during the reign of Uziyahu, there was no need for chastisement for much of his rule.</p>
 
<mekorot>perhaps <multilink><a href="REliezerofBeaugencyYeshayahu1-1" data-aht="source">R. Eliezer of Beaugency</a><a href="REliezerofBeaugencyYeshayahu1-1" data-aht="source">Yeshayahu 1:1</a><a href="REliezerofBeaugencyYeshayahu6" data-aht="source">Yeshayahu 6</a><a href="R. Eliezer of Beaugency" data-aht="parshan">About R. Eliezer of Beaugency</a></multilink></mekorot>
 
<mekorot>perhaps <multilink><a href="REliezerofBeaugencyYeshayahu1-1" data-aht="source">R. Eliezer of Beaugency</a><a href="REliezerofBeaugencyYeshayahu1-1" data-aht="source">Yeshayahu 1:1</a><a href="REliezerofBeaugencyYeshayahu6" data-aht="source">Yeshayahu 6</a><a href="R. Eliezer of Beaugency" data-aht="parshan">About R. Eliezer of Beaugency</a></multilink></mekorot>
<point><b>Chronology</b> – This position could maintain that the book is chronological. Chapter 1-5 might have been relayed during the early part of Uziyahu's reign when the nation sinned in the interpersonal sphere<fn>See <a href="Historical Backdrop of Yeshayahu 1" data-aht="page">Historical Backdrop of Yeshayahu 1</a> for elaboration on the opinion that the chapter refers to the reign of Uziyahu and might be limited to rebuke of interpersonal sins.</fn> and were overcome by arrogance.<fn>It is possible that the prosperity which marked Uziyahu's reign gave the people a false sense of their own worth, leading to Yeshayahu's cries against "כׇּל גֵּאֶה וָרָם" in Chapters 2-5.</fn> After Uziyahu was struck with <i>tzara'at </i>for his own conceit, however, the nation learned their lesson and there was no more need for rebuke until the next generation changed its ways.</point>
+
<point><b>First prophecies of the book</b> – This position could maintain that the book is chronological and that Chapter 1-5 were relayed during the early part of Uziyahu's reign when the nation sinned in the interpersonal sphere<fn>See <a href="Historical Backdrop of Yeshayahu 1" data-aht="page">Historical Backdrop of Yeshayahu 1</a> for elaboration on the opinion that the chapter refers to the reign of Uziyahu and might be limited to rebuke of interpersonal sins.</fn> and were overcome by arrogance.<fn>It is possible that the prosperity which marked Uziyahu's reign gave the people a false sense of their own worth, leading to Yeshayahu's cries against "כׇּל גֵּאֶה וָרָם" in Chapters 2-5.</fn> After Uziyahu was struck with <i>tzara'at </i>for his own conceit, however, the nation learned their lesson and there was no more need for rebuke until the next generation changed its ways.</point>
<point><b>Why re-initiate Yeshayahu specifically now?</b> With the change in ruler to the sinful Achaz<fn>Yotam co-reigned with his father after Uziyahu was struck with<i> tzara'at</i>. It is difficult to know if his entire reign overlapped with that of Uziyahu or not.&#160; If the former, it is possible that since he too was a righteous king, Yeshayahu actually did not receive any prophecies during his rule at all, and was first re-initiated when Achaz took the throne.&#160; Alternatively, if Yotam continued to rule on his own after his father's death, it is possible that Yeshayahu was re-initiated at that point since despite the king's personal righteousness, the people were corrupt. [See Divrei HaYamamm II 27:2 "וַיַּעַשׂ הַיָּשָׁר בְּעֵינֵי י"י... וְעוֹד הָעָם מַשְׁחִיתִים".]</fn> the need for rebuked was renewed and Hashem re-initiated Yeshayahu into prophecy.</point>
+
<point><b>Why re-initiate Yeshayahu specifically now?</b> With the change in ruler to the sinful Achaz<fn>Yotam co-reigned with his father after Uziyahu was struck with<i> tzara'at</i>. It is difficult to know if his entire reign overlapped with that of Uziyahu or not.&#160; If the former, it is possible that since he too was a righteous king, Yeshayahu actually did not receive any prophecies during his rule at all, and was first re-initiated when Achaz took the throne.&#160; Alternatively, if Yotam continued to rule on his own after his father's death, it is possible that Yeshayahu was re-initiated at that point since despite the king's personal righteousness, the people were corrupt. [See Divrei HaYamamm II 27:2 "וַיַּעַשׂ הַיָּשָׁר בְּעֵינֵי י"י... וְעוֹד הָעָם מַשְׁחִיתִים".]</fn> the need for rebuke was renewed and Hashem re-initiated Yeshayahu into prophecy.</point>
<point><b>The vision</b> – Yeshayahu receives a special vision of Hashem since after such a long break, hashem needs to "reintroduce Himself".&#160; There might be no special significance in the choice of appearing as a king; this might simply be the closest image to Hashem that a human can understand.</point>
+
<point><b>The vision</b> – Yeshayahu receives a special vision of Hashem since after such a long break, Hashem needs to "reintroduce Himself".&#160; There might be no special significance in the choice of appearing as a king; this might simply be the closest image to Hashem that a human can understand.</point>
 
<point><b>The punishment</b> – This approach could suggest, like Shadal above, that Hashem refers to the upcoming devastation during the reign of Achaz specifically.</point>
 
<point><b>The punishment</b> – This approach could suggest, like Shadal above, that Hashem refers to the upcoming devastation during the reign of Achaz specifically.</point>
 
</opinion>
 
</opinion>

Version as of 20:08, 30 July 2018

Yeshayahu's Mission in Chapter 6

Exegetical Approaches

This topic has not yet undergone editorial review

Initiation to Prophecy

The chapter describes Yeshayahu's appointment, where he was prepared for and received his prophetic mission.

"אֶת מִי אֶשְׁלַח...  וָאֹמַר הִנְנִי שְׁלָחֵנִי" – Rashi and the Rid point to these words as proof that the chapter speaks of Yeshayahu's appointment as prophet.
Chronology of the chapters – This position assumes that Sefer Yeshayahu is achronological, and must explain why Chapter 6 and the initiation to prophecy do not open the book:1
  • Relayed later – Shadal posits that though Chapter 6 was the first prophecy that Yeshayahu received, it was only relayed later, after the prophecies of Chapters 2-5.2
  • Thematic order preferred – Alternatively, it is possible that thematic order takes precedence over chronological order. Chapters 1-5 describe the nation's sins, while Chapter 6 (through 12) focus on their punishment. When speaking to his contemporaries, Yeshayahu could open with a prophecy of doom, since they were well aware of their misdeeds.  Yet, when ordering his prophecies for future generations, it made sense for the prophet to begin with the nation's sins, giving the reader background to understand why the decree of destruction was deserved.
"בִּשְׁנַת מוֹת הַמֶּלֶךְ עֻזִּיָּהוּ" – According to this approach it would seem that Yeshayahu was first initiated into prophecy with Uziyahu's death (as the prophecy is dated: "בִּשְׁנַת מוֹת הַמֶּלֶךְ עֻזִּיָּהוּ").  This, however, appears to contradict Yeshayahu 1:1 which states that Yeshayahu prophesied during the reign of Uziyahu.  These commentators offer various solutions to the problem:
  • Metaphoric death – Rashi and the Rid suggest that the phrase "בִּשְׁנַת מוֹת הַמֶּלֶךְ עֻזִּיָּהוּ" refers to the year when Uziyahu was struck with tzara'at and metaphorically died,3 rather than to the year of his actual death.  If so, Yeshayahu was initiated in the middle of Uziyahu's reign and prophesied for several years before his death.
  • Initiated in the year prior to Uziyahu's death – Ibn Ezra, instead, points out that the verse speaks of the year (not the day) of Uziyahu's death.4 As such, Yeshayahu could have received several months worth of prophecies during Uziyahu's reign.5
  • Date of transmission – Finally, Shadal asserts that the opening "בִּשְׁנַת מוֹת הַמֶּלֶךְ עֻזִּיָּהוּ" refers to the date that Yeshayhau relayed the prophecy,6 not to the year in which he received it.7
Vision of Hashem – Since this is Yeshyahu's first prophecy it is logical why he merits a vision of Hashem.  This is comparable to the opening prophecy of Yechezkel who also sees "מַרְאוֹת אֱלֹהִים".
"...אוֹי לִי כִי נִדְמֵיתִי" – Rashi, Rid and Shadal explain "נִדְמֵיתִי" to mean "‎‏‎נכרתי".‎8 Yeshayahu thought that he was deserving of death since he was unworthy of seeing Hashem's glory.
"וְסָר עֲוֺנֶךָ וְחַטָּאתְךָ תְּכֻפָּר" – According to the Rid and Shadal, Hashem is not referring to any specific sin for which Yeshayahu needed atoning,9 but to a general purification process. As Yeshayahu begins his task as Hashem's messenger and spokesman, Hashem prepares him by cleansing him of all sins and purifying his mouth.10
The task – These sources differ in their understanding of Hashem's mission to Yeshayahu and what is meant by the statements: "שִׁמְעוּ שָׁמוֹעַ וְאַל תָּבִינוּ" and "הַשְׁמֵן לֵב הָעָם הַזֶּה...  פֶּן יִרְאֶה בְעֵינָיו...  וָשָׁב וְרָפָא לוֹ"
  • Description of future – According to Rashi, Hashem is not commanding that the people should not understand nor that Yeshayahu should actively harden their hearts, but simply sharing what will happen in the future.11 Despite all of Yeshayahu's chastisements, the nation will refuse to heed his words and repent.  At the beginning of his assignment, Hashem warns Yeshayahu that he is volunteering for a doomed mission, for he will not be successful.12
  • Command – The Rid, Ibn Ezra and Shadal,13 in contrast, explain that these words constitute a command.14 Due to the nation's many sins,15 the decree of destruction was set, and the people were to be actively prevented from repenting. [For various approaches to the theological question of how Hashem can remove someone's free will and keep them from repenting, see Hardened Hearts.] As such, Yeshayahu's task was not be to bring the people back to Hashem, but simply to warn them of the impending destruction.16
"עַד אֲשֶׁר אִם שָׁאוּ עָרִים מֵאֵין יוֹשֵׁב" – Hashem tells Yeshayahu that the situation will last until "שָׁאוּ עָרִים מֵאֵין יוֹשֵׁב," and that even those who survive will be punished afterwards ("וְעוֹד בָּהּ עֲשִׂרִיָּה וְשָׁבָה וְהָיְתָה לְבָעֵר"). These sources disagree regarding both the context of the initial destruction and the identity of the "tenth" who will secondarily be consumed.
  • Exile of Ten Tribes – According to the Rid, the verses refer to the destruction and exile17 of the Ten Tribes. Yehuda represents the remaining tenth who is also to be burnt at the hands of Sancheriv, but will ultimately survive and thrive, "כָּאֵלָה וְכָאַלּוֹן אֲשֶׁר בְּשַׁלֶּכֶת מַצֶּבֶת בָּם זֶרַע קֹדֶשׁ מַצַּבְתָּהּ".
  • Exile of Yehuda – Ibn Ezra, in contrast, suggests that the verses refer only to the Southern Kingdom, and speak of the exile of Yehuda itself.  This, though, will only occur after ten kings' reigns (וְעוֹד בָּהּ עֲשִׂרִיָּה).18 [Alternatively, one could suggest that the "tenth" refers to those who remained in the land under the rule of Gedalayah, who were then also forced to flee.] The phrase "זֶרַע קֹדֶשׁ מַצַּבְתָּהּ"' refers to the returnees from Babylonia.
  • Destruction in time of Achaz – Shadal uniquely places the destruction much earlier, in the reign of Achaz,19 when Yehuda was attacked first by Aram and Yisrael,20 and then also ("וְשָׁבָה וְהָיְתָה לְבָעֵר") by the Edomites and Philistines. The holy seed that ultimately survives is Chizkiyahu, who is able to reform the country as a whole.21 [According to Shadal, then, Hashem's initiation message to Yeshayahu refers not to his entire tenure as prophet but only to the first part thereof. He will initially be met with resistance, but not always.]
Intended audience of the prophecy
  • According to this approach it is possible that Yeshayahu was never meant to transmit this prophecy to the nation at all, and it was aimed at him alone.22  In fact, the prophecy of destruction at the end might not have been relayed even to Yeshayahu at this stage, had it not been for his question "עַד מָתַי".
  • Shadal agrees in principle, and suggests that for many years Yeshayahu kept the prophecy to himself.  Yet, at some point, when the people not only refused to listen but actively mocked him (Yeshayahu 5:18-20), Yeshayahu relayed the prophecy to show them that their refusal to listen was actually preordained, and in fact, part of their punishment.
Biblical Parallels

Unique Mission

Since the prophecy of Chapter 6 sealed the fate of Israel, foretelling their exile, it was relayed to Yeshayahu in an exalted fashion, matching the intensity of the mission.

Chronology of the book – This position can maintain chronological order in the book, as it does not assume that this was Yeshayahu's first prophecy.
The vision – Since Hashem is sending Yeshayahu on an especially harsh mission, He reveals Himself at the beginning of the prophecy so that there can be no mistaking that the punishment about to be announced was issued by Hashem.  Moreover, He appears to the prophet as a king sitting on His throne, as if to say the decree of destruction is a royal edict not to be changed.
"וְהַבַּיִת יִמָּלֵא עָשָׁן" – Radak suggests that the smoke filling the hall represents Hashem's anger at Israel.  The trembling of the doorposts might be explained similarly, further evidence of the fear instilled by Hashem's wrath.23
"אוֹי לִי כִי נִדְמֵיתִי" – Upon seeing Hashem's anger,24 Yeshayahu cries out, "אוֹי לִי כִי נִדְמֵיתִי," assuming that he, like the rest of Israel, will be destroyed for their sins.25
"וְסָר עֲוֺנֶךָ וְחַטָּאתְךָ תְּכֻפָּר" – Hashem symbolically purifies Yeshayahu, telling him that he need not fear, for any sin of his has been atoned.
"אֶת מִי אֶשְׁלַח... וָאֹמַר הִנְנִי שְׁלָחֵנִי" – Abarbanel suggests that Hashem asked for volunteers for this mission specifically since it was such a difficult one;26 the prophet was to be tasked with telling the people that there was no hope left for them and they should despair of salvation.27
"שִׁמְעוּ שָׁמוֹעַ וְאַל תָּבִינוּ" – According to the fist option brought by Radak, these words are in the imperative; Hashem tells Yeshayhau to tell the nation that due to their sins He is preventing them from repenting. They will listen but not understand. Their hearts will be fattened so that they can not repent. The decree of punishment is immutable.28
"עַד אֲשֶׁר אִם שָׁאוּ עָרִים מֵאֵין יוֹשֵׁב... וְרִחַק י"י אֶת הָאָדָם" – Abarbanel explains that this refers to the exile of the Ten Tribes. The people's sins finally sealed their punishment, spelling the end of the Northern Kingdom. It is this devastating news that merited the unique vision.
"וְעוֹד בָּהּ עֲשִׂרִיָּה וְשָׁבָה וְהָיְתָה לְבָעֵר כָּאֵלָה וְכָאַלּוֹן אֲשֶׁר בְּשַׁלֶּכֶת מַצֶּבֶת בָּם" – Radak explains that Hashem shares that after ten kings' reigns,29 Yehuda, too, will be punished and exiled, but in contrast to the Ten Tribes who are lost forever, they will eventually return.  Like trees who lose their leaves in the winter and appear dried out and dead, but rejuvenate in the spring, so, too, Yehuda will once again thrive.30
Yeshayahu's audience
Biblical Parallels – It is possible that Yechekel's vision of Hashem in the opening chapters of his book served a similar purpose to this prophecy.  There, too, the vision is accompanied by news of devastation, Hashem's decision to destroy the Mikdash, remove His presence, and exile Yehuda.

Re-initiation to Prophecy

Yeshayahu's vision of Chapter 6 constitutes a second call to prophecy, after a hiatus in which he had not received the word of Hashem. This position divides regarding the reason for the break:

Yeshayahu Resigned

When the nation refused to heed Yeshayahu's words and mocked the punishments he forewarned, Yeshayahu gave up and stopped rebuking the people.

Mocking of Yeshayahu – This position points to Yeshayahu 5:18-20 as evidence that the nation did not believe in Yeshayahu's prophecies and assumed that they would not be punished for their deeds.31 [There is no explicit evidence in the verses, however, that Yeshayahu therefore refrained from further chastisement.]
Chronology of the book – This position can maintain chronological order in the book, as it does not view Chapter 6 as Yeshayahu's first prophecy.
The vision – Yeshayahu receives a grandiose vision of Hashem on His throne since this is a re-initiation into prophecy, and not merely a new message.
"וְהַבַּיִת יִמָּלֵא עָשָׁן" – The smoke might be symbolic of Hashem's anger and disappointment in Yeshayahu for having abandoned his task.
"אוֹי לִי כִי נִדְמֵיתִי" – This position understands "נִדְמֵיתִי" to mean "I was silent". With Hashem's renewed revelation ("כִּי אֶת הַמֶּלֶךְ י"י צְבָאוֹת רָאוּ עֵינָי"), Yeshayahu was ashamed that he had decided to remain silent and had not continued to rebuke the people despite their taunts ("עַם טְמֵא שְׂפָתַיִם").32
"וְסָר עֲוֺנֶךָ" – Hashem reassures Yeshayahu that he is forgiven and purges him of any guilt.
"אֶת מִי אֶשְׁלַח... וָאֹמַר הִנְנִי שְׁלָחֵנִי" – Hashem gives Yeshayahu the opportunity to prove that he is once again willing to prophesy by asking "אֶת מִי אֶשְׁלַח".  Yeshayahu immediately replies in the positive, volunteering to embark on Hashem's mission.
"שִׁמְעוּ שָׁמוֹעַ וְאַל תָּבִינוּ' – Hashem's words can be understood as either encouragement or a warning to the prophet:
  • Encouragement – Hashem explains to Yeshayahu that the reason the people had refused to change was because Hashem had hardened their hearts, ensuring that they would hear but not understand.  It was Hashem who was preventing them from repenting.
  • Warning – Hashem warns Yeshayahu that if he re-accepts Hashem's mission, he must do so with the full knowledge that the people are going to continue to refuse to listen.
Punishment
Biblical Parallels
  • Eliyahu – According to some opinions, Eliyahu's flight to Chorev marked his desire to stop prophesying.  In its aftermath, he, too, receives an elaborate vision of Hashem in which he is re-inititaed into prophecy. For elaboration, see Eliyahu at Chorev
  • Moshe –

Yeshayahu Sinned

When Uziyahu was struck with tzara'at, Yeshayahu was dismayed at the injustice of the punishment.  He had thought the king a righteous individual and undeserving of such a fate. This sinful doubting of Hashem's justice precluded him from receiving further prophecy.

Sources:Abarbanel
The Vision: "יֹשֵׁב עַל כִּסֵּא רָם וְנִשָּׂא וְשׁוּלָיו מְלֵאִים אֶת הַהֵיכָל" – Hashem's vision was meant to teach Yeshayahu why Uziyahu deserved his punishment.  Uziyahu had sinned both in arrogance and in assuming that there is no individual providence, thinking he could bring an incense offering and that Hashem would not notice.33 Hashem shows Himself to Yeshayahu in all His grandeur both to highlight how lowly people are compared to God, and to teach that despite His exalted stature, Hashem still fills the "הֵיכָל" and is aware of what every individual in the world is doing.34
"אוֹי לִי כִי נִדְמֵיתִי... וְסָר עֲוֺנֶךָ" – According to Abarbanel, the word "נִדְמֵיתִי" means "I imagined". Yeshayahu realizes that he has been mistaken in thinking that Uziyahu was undeserving of punishment and cries out that he is sorry that he has imagined injustice where there was none.
"כִּי אִישׁ טְמֵא שְׂפָתַיִם אָנֹכִי" – Yeshayahu is of "impure lips" because he (like the nation as a whole) had defended Uziyahu despite the king's guilt.
"וְסָר עֲוֺנֶךָ" – Hashem has the angel place a burning coal on Yeshayahu's lips to both punish him and atone for his sin.
"אֶת מִי אֶשְׁלַח... וָאֹמַר הִנְנִי שְׁלָחֵנִי" – After Yeshayahu is forgiven, he once again receives prophecy.  Yeshayahu volunteers for Hashem's mission to show his willingness to rebuke the people, promising not to defend them (as he had defended Uziyahu)  if unwarranted.
The mission: "שִׁמְעוּ שָׁמוֹעַ וְאַל תָּבִינוּ" – Abarbanel claims that Hashem never locks the gates of repentance, and that Hashem is simply telling Yeshayahu is advance that the people will refuse to listen and change.
"וְרִחַק י"י אֶת הָאָדָם" – Abarbanel assumes this refers to the exile of the Ten Tribes.

Yeshayahu Unnecessary

Since the people had not forsaken Hashem during the reign of Uziyahu, there was no need for chastisement for much of his rule.

First prophecies of the book – This position could maintain that the book is chronological and that Chapter 1-5 were relayed during the early part of Uziyahu's reign when the nation sinned in the interpersonal sphere35 and were overcome by arrogance.36 After Uziyahu was struck with tzara'at for his own conceit, however, the nation learned their lesson and there was no more need for rebuke until the next generation changed its ways.
Why re-initiate Yeshayahu specifically now? With the change in ruler to the sinful Achaz37 the need for rebuke was renewed and Hashem re-initiated Yeshayahu into prophecy.
The vision – Yeshayahu receives a special vision of Hashem since after such a long break, Hashem needs to "reintroduce Himself".  There might be no special significance in the choice of appearing as a king; this might simply be the closest image to Hashem that a human can understand.
The punishment – This approach could suggest, like Shadal above, that Hashem refers to the upcoming devastation during the reign of Achaz specifically.