This verse is part of a speech given by Rabshakeh, an Assyrian official, to the people of Jerusalem during the siege by the Assyrian army. Rabshakeh is trying to undermine the confidence of the Judeans in their ability to resist the Assyrians. The verse specifically targets their reliance on Egypt for help.

Here's a breakdown of the verse's meaning:

"Now, behold, you trust in the staff of this bruised reed, even in Egypt." This is the core argument. Rabshakeh is saying that the Judeans are foolishly relying on Egypt for support. He uses the metaphor of a "bruised reed" to describe Egypt. A reed is a weak plant to begin with, and a bruised one is even weaker and more likely to break. He's implying Egypt is weak and unreliable, a broken reed offering false support.

"If a man leans on it, it will go into his hand, and pierce it." This illustrates the danger of relying on a broken reed. Instead of providing support, it will injure the one leaning on it. This means that instead of helping Judah, Egypt will ultimately harm them.

"So is Pharaoh king of Egypt to all who trust on him." This connects the metaphor to the reality of the situation. Rabshakeh explicitly states that Pharaoh, the king of Egypt, is like the bruised reed. He's saying that anyone who trusts in Pharaoh and Egypt will be disappointed and ultimately hurt. Egypt's promised support will backfire and lead to negative consequences.

In essence, Rabshakeh's message is this:

Don't trust Egypt. They are weak and unreliable.
Relying on Egypt will only lead to your downfall.
You are better off surrendering to Assyria.

It's important to remember that Rabshakeh is a propagandist. He's trying to scare the Judeans into surrendering. He's painting a negative picture of Egypt to weaken their resolve and make Assyria's victory easier. He is not necessarily an unbiased or truthful reporter on the state of Egypt.

The verse demonstrates the use of vivid imagery and metaphor to deliver a powerful message aimed at swaying public opinion during a time of crisis.