Behold, the Lord will come with fire. "Fire" is a usual accompaniment of a "theophany." God descended on Sinai "in fire" (Exodus 19:18), and led the Israelites through the wilderness by the pillar of the cloud and of fire (Exodus 13:21, Exodus 13:22), and filled the tabernacle with a glory as of fire (Exodus 40:34), and "answered David from heaven by fire upon the altar of burnt offering'' (1 Chronicles 21:26), and in the same way answered Solomon (2 Chronicles 7:1) and Elijah (1 Kings 18:38).
Isaiah almost always describes a theophany as a "coming with fire" (see Isaiah 10:16-18; Isaiah 27:4; Isaiah 29:6; Isaiah 30:27, Isaiah 30:30; Isaiah 33:12, Isaiah 33:14, etc.). The agency of fire in the judgment that will overtake the wicked simultaneously with Christ's second coming, appears in 2 Thessalonians 1:8; 2 Peter 3:7-10.
With his chariots (comp. Psalms 68:17; Habakkuk 3:8). "Chariots," in the plural, may be regarded as symbolizing the "hosts" of natural and supernatural forces that God has at his command (Cheyne). Like a whirlwind.
The whirring of the wheels of chariots, their noise, the swiftness of their pace, and the destruction that they cause, make this simile most appropriate. To render his anger; or, to expend his anger—to vent it.