Albert Barnes Commentary Isaiah 29:6

"She shall be visited of Jehovah of hosts with thunder, and with earthquake, and great noise, with whirlwind and tempest, and the flame of a devouring fire." — Isaiah 29:6 (ASV)

You will be visited - This is an address to the mighty army of the Assyrian. Such transitions are not uncommon in the writings of Isaiah. His eye seems to have been directed in vision to the hosts of Sennacherib, and to their sudden dispersion and destruction (Isaiah 29:5), and by a sudden, but not unnatural transition, he turns and addresses the army itself, with the assurance that it should be punished .

With thunder ... - The army of the Assyrian was cut off by an angel sent forth from God (Isaiah 37:36). It is possible that all the agents here referred to may have been employed in the destruction of the Assyrian host, though they are not particularly specified in the history. But it is not absolutely necessary to understand this verse in this manner. The image of thunder, earthquakes, and lightning, is an impressive representation of sudden and awful judgment in any manner. The sense is, that they should be suddenly destroyed by the direct visitation of God (Isaiah 26:11).

And the flame of devouring fire - Lightning, that seems to devour, or that suddenly consumes.