"What shall one then answer the messengers of the nation? That the LORD hath founded Zion, and the poor of his people shall trust in it." (Isaiah 14:32)
These messengers may be the Philistines who would come and inquire of Isaiah concerning his prophecies against them, or they may be those who came to solicit the assistance of Judah against the Assyrians.
At least twice, Judah was approached by Philistia with offers of an alliance. The first attempt to gain Judah's aid was made by the king of Ashdod who revolted against Sargon in 711 BC. The prophecies against the Egyptian and Ethiopian allies of Philistia in Isaiah 20:1-6 may be what prevented King Hezekiah from joining this first offer of an alliance.
The second offer came when Ashdod, Ashkelon and Ekron revolted against the new ruler Sennacherib sometime near 705/704 BC. Hezekiah did join this coalition, and his attempts to prepare for the retaliation of Sennacherib can be seen in II Chronicles 32:1-8.
In this verse, the reader finds the thoughts of the Holy Spirit concerning the matter of alliances with the ungodly. JEHOVAH of the armies has founded Zion, and its rulers need not trust in any man. Just because Hezekiah did join in a coalition against Assyria, it does not mean that God was in favor of the decision. This verse here in Isaiah firmly establishes God's desire for Judah. She was to be steadfast in faith toward God. She was to fear Him. She was to serve Him. If the poor in spirit as well as the poor in possessions would trust in the reality of God's preserving power, they would be delivered.
What then is the saint's response to be concerning alliances with the ungodly in any dispensation? "...The LORD hath founded Zion, and the poor of his people shall trust in it."