Yeshayahu's words constitute a prophecy of consolation and encouragement. This approach subdivides regarding the event about which Achaz is being comforted:
The Aramean-Israelite Threat
All of Yeshayahu's words relate to the threat posed by the Aramean-Israelite alliance. Yeshayahu tells Achaz that he need not worry since both countries are soon to be destroyed by Assyria.
Single message – One of the advantages of this approach is that it presents Yeshayahu as speaking about only one issue, with one unified message, throughout the chapter. Everything the prophet says relates to the downfall of Aram and Israel.
Anger regarding the sign – According to this approach, despite Yeshayahu's anger at Achaz for refusing a Divine sign, the prophet continues to promise Hashem's aid and encourage the king that he has nothing to fear from his enemies.
"יָבִיא י"י עָלֶיךָ... יָמִים אֲשֶׁר לֹא בָאוּ לְמִיּוֹם סוּר אֶפְרַיִם מֵעַל יְהוּדָה" – Despite first impressions, these words need not connote that calamity is to befall Yehuda, as the term "יָבִיא י"י עָלֶיךָ" can relate to good tidings as well as bad.2 Yeshayahu is prophesying that with the fall of Israel at the hand of Assyria,3 the state of the nation will revert to what it had been before the split of the kingdom (לְמִיּוֹם סוּר אֶפְרַיִם מֵעַל יְהוּדָה), when there was just one monarch who ruled over the entire country.4 This might reflect hopes that Chizkiyahu was to revive the Davidic dynasty of old,5 take control of the Northern kingdom, and be a Messianic type of figure.6
Flies of Egypt and bees of Assyria – According to this approach, the mention of the "זְּבוּב אֲשֶׁר בִּקְצֵה יְאֹרֵי מִצְרָיִם" is not intended to connote that Egypt was to join forces with Assyria; it is simply a metaphor for any vast army. As such, the image of both the flies and the bees refer to the swarms of Assyrian soldiers who were to fall upon Aram and Israel.
"תַעַר הַשְּׂכִירָה" – According to this position, the words "מֶלֶךְ אַשּׁוּר" serve to identify the "תַעַר הַשְּׂכִירָה". Assyria is likened to a "razor" as it is about to raze the lands of Aram and Israel until not a hair is left. This approach might agree with Rashi Yeshayahu 7:15-25About R. Shelomo Yitzchakithat "הַשְּׂכִירָה" refers to an honored or important person (or nation),7 rather than a hired hand.
"Butter and honey" – This approach could read the two appearances of the image in one of two ways:
Blessing of prosperity – In both verses 15 and 22, the eating of "butter and honey" is a metaphor for blessings which will benefit Yehuda. Yeshayahu declares that after Aram and Israel are defeated, the cattle of the Judeans8 will give forth so much milk that butter will be made from the leftovers. This positive understanding of the image might be supported by its similarity to the phrase "אֶרֶץ זָבַת חָלָב וּדְבָשׁ", a description which consistently has a positive connotation in Tanakh.
Prosperity and desolation – Alternatively, while the image in verse 15 connotes blessing, in verse 22 the excessive butter signifies the desolation in Aram and Israel. Yeshayahu tells Achaz that due to the Assyrian invasion, all agricultural produce in his enemies' countries will be ruined, so that the refugees from war will have only milk to consume. According to this reading, everything in verses 18-25 refers to the destruction which will take place in Aram and Israel.9 The prophet might intentionally uses the same image in contrasting ways because the desolation brought to Yehuda's enemies is what will allow Achaz' own land to thrive.
"לַשָּׁמִיר וְלַשַּׁיִת יִהְיֶה" – The description of desolation in verses 23-25 relates to the lands of Aram and Israel. After they are subdued by Assyria, the land will be barren and overgrown. This would fit with Yeshayahu's earlier promise to Achaz in verse 15: "כִּי בְּטֶרֶם יֵדַע הַנַּעַר מָאֹס בָּרָע וּבָחֹר בַּטּוֹב תֵּעָזֵב הָאֲדָמָה אֲשֶׁר אַתָּה קָץ מִפְּנֵי שְׁנֵי מְלָכֶיהָ".10
Both the Aramean-Israelite and the Assyrian Threat
Yeshayahu tells Achaz that he has nothing to fear from Aram and Israel, since Assyria is soon to ravage both countries. Though Assyria will invade Yehuda as well, Yehuda will survive and Sancheriv's army will be defeated.
"יָבִיא י"י עָלֶיךָ... אֵת מֶלֶךְ אַשּׁוּר" – These sources understand this verse to mean that Yehuda, too, will be attacked by Assyria. Yeshayahu tells Achaz that though he has nothing to fear from Aram and Israel, he should worry about Assyria. He will be plagued by Tiglat Pilesser, and his son, Chizkiyahu,11 will be by attacked by Sancheriv.
"יָמִים אֲשֶׁר לֹא בָאוּ לְמִיּוֹם סוּר אֶפְרַיִם מֵעַל יְהוּדָה" – Yeshayahu compares the attack of Sancheriv to the split of the kingdom to emphasize the enormity of the danger and devastation. This is the first time since the split that Yehuda will find herself in such dire straits, with the potential to lose her land.
Flies and bees
"תַעַר הַשְּׂכִירָה" – These sources do not identify the "תַעַר הַשְּׂכִירָה" with Assyria, but rather present Yeshayahu as saying that Hashem will use his "blade" to raze Assyria. They suggest that the verse refers to the angel and plague which decimated Sancheriv's army and caused him to retreat. As such, this verse represents the turning point in the prophecy, introducing the consolation. Though Assyria is to attack, Yehuda is to be saved.
"Butter and honey" – According to these sources, the image in both verses 15 and 22 can refer to the same blessing. Ibn Ezra, Radak and Abarbanel explain that in the aftermath of Sancheriv's campaign the surviving righteous will be able to subsist on even a single calf or two sheep since they will be so productive. The milk will be so abundant that they will dismiss it and drink only of the fat. [Alternatively, they will have no choice but to make butter from the leftovers.]
"לַשָּׁמִיר וְלַשַּׁיִת יִהְיֶה" – These sources struggle to find the message of consolation in verses 23-25, and are forced to interpret the verses against their simple sense:
Rashi asserts that the verse suggests that all the vineyards will be overgrown with thorns because the generation of Chizkiyahu will be busy learning Torah and scorn wine. In the hills, in contrast, there will be no fear of bramble (לֹא תָבוֹא שָׁמָּה יִרְאַת שָׁמִיר וָשָׁיִת). The land there will be worked to produce grain, and provide pasture for animals.
Radak suggests to read verse 23-24 as if inverted: all the sites which today are full of bramble, and to which one will only approach with bow and arrow, will be filled with valuable vines.
Finally, Abarbanel asserts that verses 23-24 depicts the situation during Sancheriv's campaign, while verse 25 represents the promise of what will happen in its aftermath. Even the hilly land (normally home to robbers) will be worked, and there will be no fear of barreness. Due to the peacefu climate, the areas will be open to roaming oxen and sheep.
Rebuke
Yeshayahu's words constitute a rebuke to Achaz for not trusting in Hashem's promise that He will aid Yehuda. As punishment for seeking human assistance, Achaz is told that Assyria will smite not only Aram and Israel, but Yehuda as well.
Refusal to receive a sign – Achaz's refusal to ask for a sign betrayed his lack of belief in Hashem's aid, clarifying to Yeshayahu that Achaz had no intention of heeding his advice to trust in God and not seek foreign assistance ("הִשָּׁמֵר וְהַשְׁקֵט").
The sign: Emanuel – Shadal claims that due to Achaz' refusal to ask for a sign, Yeshayahu gave him one which did not suffice to calm his fears. Since the birth of Emanuel was not to be immediate, Achaz was left to his worries. This ensured that he continued on the path he had set for himself, bribing Assyria to fight against his enemies (See Melakhim II 16:8-9 and Divrei HaYamim II 28:16)
"יָבִיא י"י עָלֶיךָ... אֵת מֶלֶךְ אַשּׁוּר" – According to these sources, the words "יָבִיא י"י עָלֶיךָ" imply that Assyria will attack Yehuda itself. After telling Achaz about the fall of Aram and Israel, Yeshayahu warns Achaz that the very kingdom which he hoped would help him, will eventually turn on him and devastate his country. These sources differ regarding the specific event to which Yeshayahu refers:
Tiglat Pilesser's invasion – According to Shadal, Yeshayahu is speaking of Tiglat Pilesser himself, who attacked not only Aram and Israel but Yehuda as well. As Divrei HaYamim shares, "וַיָּבֹא עָלָיו תִּלְּגַת פִּלְנְאֶסֶר מֶלֶךְ אַשּׁוּר וַיָּצַר לוֹ וְלֹא חֲזָקוֹ".
Sancheriv's campaign – R"E of Beaugency, in contrast, assumes that Yeshayahu is referring to Sancheriv's campaign against Yehuda in the time of Chizkiyahu. the prophet speaks of a future rather than immediate punishment.12
Biblical parallels – Elsewhere in Tanakh, as well, there are similar warnings that seeking foreign aid rather than trusting in Hashem will result in catastrophe (especially when one invites a foreigner to attack one's own brother):
Turning to Aram – In Divrei HaYamim II 16, when Asa seeks Aram's help against Basha, he is rebuked by the prophet Chanani, "בְּהִשָּׁעֶנְךָ עַל מֶלֶךְ אֲרָם וְלֹא נִשְׁעַנְתָּ עַל י"י אֱלֹהֶיךָ עַל כֵּן נִמְלַט חֵיל מֶלֶךְ אֲרָם מִיָּדֶךָ".13
Turning to Egypt – Yeshayahu speaks out against going to Egypt for aid in Yeshayahu 20 and Yeshayahu 31:1-3, promising "וּמִצְרַיִם אָדָם וְלֹא אֵל וְסוּסֵיהֶם בָּשָׂר וְלֹא רוּחַ וַי"י יַטֶּה יָדוֹ וְכָשַׁל עוֹזֵר וְנָפַל עָזֻר וְיַחְדָּו כֻּלָּם יִכְלָיוּן".
Turning to Bavel – Chizkiyahu's showing of his treasures to Merodakh Baladan of Bavel has been understood as an attempt to join an alliance against Assyria.14 Yeshayahu reacts in anger, warning Chizkiyahu, "הִנֵּה יָמִים בָּאִים וְנִשָּׂא כׇּל אֲשֶׁר בְּבֵיתֶךָ וַאֲשֶׁר אָצְרוּ אֲבֹתֶיךָ עַד הַיּוֹם הַזֶּה בָּבֶלָה".
"תַעַר הַשְּׂכִירָה" – The image of a "תַעַר הַשְּׂכִירָה" refers to Assyria, so called because he had been "hired" by Achaz to attack Aram and Israel.15
"אֶת הָרֹאשׁ וְשַׂעַר הָרַגְלָיִם וְגַם אֶת הַזָּקָן תִּסְפֶּה" – The description of razing from head to feet would seem to suggest a totality of destruction. This would fit the campaign of Sancheriv when all of the fortified cities of Yehuda were conquered and only Yerushalayim remained, but would appear not to be an appropriate description of the invasion of Tiglat Pilesser. This leads Shadal to suggest that the image of "shaving" is intentionally used because it implies a cutting of the hair, but not the skin. Tiglat Pilesser's soldiers plundered and ravaged the land, but did not actually battle and cause bloodshed.16
Flies of Egypt – This approach might suggest that Egypt is mentioned, not because they joined forces with Assyria against Yehuda, but because they were another enemy country which Judean kings relied upon and turned to for assistance when dealing with foreign affairs.17 Yeshayahu tells Achaz that any empire in whom he will trust rather than Hashem will ultimately not only fail him, but turn into a foe.18
Butter and honey – According to Shadal. the same image is used to connote opposite concepts in verses 15 and 22. In verse 15, the promise that Emanuel will eat fat and honey is a sign of the upcoming salvation from Aram and Israel, while in verse 22 it signifies the devastation to be wrought on Yehuda. Since all the agricultural land will be laid barren by the Assyrian forces,19 the only thing that will be left to eat will be the milk produced by cattle. It is possible that the prophet intentionally used the same image to highlight how Achaz' lack of belief turned a promise of blessing into a curse.
"לַשָּׁמִיר וְלַשַּׁיִת יִהְיֶה" – This description of devastation refers to the aftermath of Assyria's attack on Yehuda. Yehuda will be barren, her fruitful vines laid to waste and her land filled with thorns.20 This description could match either of the eras discussed above as being the setting of Yeshayahu's words:
Era of Achaz – Chizkiyahu says of his father's reign: "וַיְהִי קֶצֶף י"י עַל יְהוּדָה וִירוּשָׁלִָם וַיִּתְּנֵם [לְזַעֲוָה] (לזועה) לְשַׁמָּה וְלִשְׁרֵקָה" (Divrei haYamim II 29:8).,.