Sorrow Awaiting Those Who Trust Human Strength
The Futility of Egypt (1-3)
Chapter 31 continues in the "sorrows await” format, focusing His attention on those who choose to trust in the might and wisdom of earthly military and rulers over the Almighty, Holy One of Israel (1). Yahweh reminds Judah He does not take His word back but will do what He said He would do to the evil (2). Yahweh then contrasts His own might and power to that of the Egyptians, reminding the people that the difference is a matter of relying on flesh and blood vs. relying on the One who created all flesh and blood. In the end, those who helped Judah and Judah itself would fall (3).
Yahweh Spares (4-9)
Yahweh will not be frightened by the growling predator seeking to destroy Judah (4). So connected is Yahweh—like an eagle protecting her eggs, she will not allow total destruction.
Though the people turn to the Egyptians for help, the Lord stays faithful to His people in their time of need, comforting and protecting them. The Lord will keep watch over His people and will cause dread and terror in the hearts of all their enemies (5).
The help of the Lord does not come without a call to repentance for their idolatry and turning to the Lord as the One True God (see Deuteronomy 6:4-5). This is because the Lord warns that there will come a day when all idols that people have made and put their trust in will be cast down and destroyed. Therefore, for those who have placed their hope and trust in those idols, then in that day all hope will be lost (7).
Isaiah then prophesies of the great moment when Yahweh would take His sword and destroy 185,000 Assyrians in one night. His fierce judgment would create such panic and terror in the enemy of Judah that even their bravest would quake (8-9).