A hope hidden?

In reading about call, I am comparing Moses, Isaiah, Jeremiah, and Ezekiel.

What I noticed today is that God is sending these prophets to speak to people and yet God knows they will not listen.  He sends Moses to Pharaoh, and God knows his heart will be hardened.  He sends Isaiah to speak to a "sinful" nation, and he knows they will not comprehend.  He sends Jeremiah to a country that God says "shall be put to shame." He sends Ezekiel to speak to a rebellious house -- "they will not listen to you."

And yet God sends them anyway.

Is there a kind of hope in those desolate statements?