Let's look how this predicted Day of the Lord of Isaiah turned out - God would descend out of heaven, with a shout, in devouring fire, with hailstones, with a scattering and tempest, in the Day of His Wrath.
(Isa 30:30 KJV) And the LORD shall cause his glorious voice to be heard, and shall show the lighting down of his arm, with the indignation of his anger, and with the flame of a devouring fire, with scattering, and tempest, and hailstones.
The Assyrian judgment and reversal of Israel's fortunes was to happen - "Is it not yet a very little while".
(Isa 29:17 KJV) Is it not yet a very little while, and Lebanon shall be turned into a fruitful field, and the fruitful field shall be esteemed as a forest?
(Isa 37:36 KJV)
Then the angel of the LORD went forth, and smote in the camp of the Assyrians a hundred and fourscore and five thousand: and when they arose early in the morning, behold, they were all dead corpses.
Was the language used for this Day of the Lord fulfilled literally?
Was there a bodily coming of God from heaven - no.
Was there a "glorious voice" heard - no
Was there a literal rain of devouring fire or hail - no.
The people of Jerusalem were unaware of what had happened in the Assyrian camp until scouts came across them the next morning.
And note - the sun did not become seven times brighter than normal even though Assyria was defeated, and Israel delivered.
The moon did not become as bright as the sun. Neither did rivers and streams suddenly break out on the tops of the mountains and hills. (Fades in track from the Sound of Music....the hills are alive with the sound of rivers....)
You people may as well be reading Mary Poppins.