Isaiah moves to a new theme. In this case, Jehovah is discussing the Assyrian invasion. Isaiah has previously noted that Assyria is as a hired hand for Jehovah. That is the imagery here. The Lord speaks to the Assyrian, and declares that Assyria is the means of the destruction that Jehovah had declared, initiated, and approved. It is the “rod of mine anger.” Jehovah notes that “I will send him against a hypocritical nation.” This is not Assyria’s war, but rather Jehovah’s.
Nevertheless, verse 7 notes that the king of Assyria does not realize that he is a tool rather than an initiator. Although Jehovah declares that it is God’s war, the Assyrian king does not think it is. The Assyrian king is bent on the destruction of nations, and believes that this is just a part of that overall plan.
An important allusion comes in verse 6, where Jehovah says that he will charge the Assyrian “to take the spoil, and to take the prey.” This references the prophetic name of Isaiah’s son Maher-shalal-hash-baz, which means “hasten to the plunder and quick to the spoil.” The name of the second son will be invoked later in verse 21.