When Ephraim saw his sickness, And Judah his wound, Then Ephraim went to Assyria, And sent to king Jareb: But he is not able to heal you, Neither will he cure you of your wound.
"And sent to king Jareb ..." There is no knowledge whatever of who this "king Jareb" might have been; and this is exactly the kind of problem that delights Biblical commentators.  There are about as many guesses as their are scholars.  Harper compiled a list of opinions, giving the following explanations:[30]