Assyria now comes to attack Judah. Assyria is the strongest nation at the time, and they assume that means they have the strongest gods. Since Hezekiah has destroyed all of the idols in Judah, they assume those gods will be unhappy and won’t protect Judah. Given the situation, the Assyrians begin to insult the nation, their king and their God. God steps in and destroys their army. Historians say the entire region fell to the Assyrians except for Jerusalem. Later in the chapter, we are told that Hezekiah becomes proud, but he recognizes his sin, and God allows Judah to continue.
It is common for people to insult God today. They make fun of him and those who believe in him. Although they may succeed for a time, God will demonstrate his power in his time.