Most commentators say this prophecy was fulfilled during the reign of Hezekiah, that he was the king who reigned in righteousness. While parts of it may apply to Hezekiah, I believe the prophecy is of the Messianic kingdom. God’s paragraph divisions, which reveal a chiastic structure, make this more clear:
1A: Isa 32:1-20, A King will reign in righteousness + the effect of righteousness;
1B: Isa 33:1, Woe to the plunderer and the treacherous;
1C: Isa 33:2-5a, Grace + salvation + the LORD lifts Himself up + is exalted;
1D: Isa 33:3b-4, He will scatter the nations + gather His plunder;
CENTRAL AXIS: Isa 33:5-6, “The LORD is exalted, for He dwells on high; He has filled Zion with justice and righteousness. Wisdom and knowledge will be the stability of your times, and the strength of salvation; the fear of the LORD is his treasure;”
2D: Isa 33:7-9, Desolation of men + fruitfulness ceases;
2C: Isa 33:10, The LORD lifts Himself up to save + is exalted;
2B: Isa 33:11-12, People cast into the fire as thorns;
2A: Isa 33:13-24, The King in his beauty + the effect of righteousness in Zion.
The description of Zion in security and peace, a quiet habitation as a tabernacle that will never be taken down, is clearly a description of Jerusalem during the reign of King Yeshua, and not Hezekiah — for future to Hezekiah is the destruction of Jerusalem and the Temple, not the peace, quietness, and stability prophesied here.
Furthermore, the prophecy of the Spirit being poured out on men from on high (Isa 32:15), after which fruitfulness, justice, and righteousness will be the rule, is also an event future to Hezekiah but connected with Messiah Yeshua.
The picture being painted here is of the reign of the righteous King, Messiah Yeshua. People are waiting for Him to return bodily and begin His reign from Jerusalem and subdue the nations, and that will happen. But as the imagery of the reign of righteousness is mixed with the outpouring of the Spirit and the salvation by grace which the LORD will accomplish for Himself, we need to consider something:
All those who are His do not need to wait for Him to return to begin living under His reign. The fruitfulness of the Spirit is available to us right now. Obedience to His commands as King is available to us right now. In these uncertain times, what will be our stability and our treasure? Not sound statecraft or wise economic policy, but wisdom and knowledge, salvation, and the fear of the LORD (Isa 33:6). Wisdom, which begins with the fear of the LORD, and the knowledge of the Holy One and His ways, to walk in them. The man who lives like this will have a secure place of defense, his bread and water will surely be supplied to him (Isa 33:16).
We should also note that Zion during the Messianic Kingdom will celebrate the appointed feasts of the LORD (Isa 33:20) — something to think about for those of us wanting to live under the righteous reign of Messiah Yeshua beginning today!