This verse is a boast spoken by the Assyrian king Sennacherib's official, the Rabshakeh, during Assyria's siege of Jerusalem. It's a key piece of propaganda designed to demoralize the people of Jerusalem and convince them to surrender. Here's a breakdown of its meaning:

Context: The Assyrians were a major power in the ancient Near East, and they had conquered many cities and nations. Sennacherib was attempting to intimidate Hezekiah, the king of Judah, into surrendering Jerusalem without a fight.
"Where are the gods of Hamath, and of Arpad? Where are the gods of Sepharvaim, of Hena, and Ivvah?" The Rabshakeh is listing cities that Assyria had already conquered. He's emphasizing that each of these cities had their own gods, yet those gods were powerless to save their people from Assyrian domination.
"Have they delivered Samaria out of my hand?" Samaria was the capital of the northern kingdom of Israel, which Assyria had already conquered some years earlier. The Rabshakeh is using Samaria as a more recent and powerful example. Even a relatively large and prominent kingdom like Israel, with all its religious institutions and traditions, couldn't withstand the Assyrian army.
The underlying message: The Rabshakeh is essentially saying: "Your god is no different. All these other cities trusted in their gods for protection, but they failed. Your god Yahweh is just as weak and powerless. Don't be foolish and resist us; surrender now, because your god can't save you."

In summary: The verse is a rhetorical question meant to undermine the faith of the people of Jerusalem in their god, Yahweh. It's a calculated attempt to use fear and religious doubt as a weapon of war. The Rabshakeh is suggesting that Yahweh is no more powerful than the gods of other conquered nations and that resistance is futile.