What do you make of the following text from 2 Kings 20 (with bolding added by me):
1 In those days Hezekiah became ill and was at the point of death. The prophet Isaiah son of Amoz went to him and said, "This is what the LORD says: Put your house in order, because you are going to die; you will not recover." 2 Hezekiah turned his face to the wall and prayed to the LORD, 3 "Remember, O LORD, how I have walked before you faithfully and with wholehearted devotion and have done what is good in your eyes." And Hezekiah wept bitterly. 4 Before Isaiah had left the middle court, the word of the LORD came to him: 5 "Go back and tell Hezekiah, the leader of my people, 'This is what the LORD, the God of your father David, says: I have heard your prayer and seen your tears; I will heal you. On the third day from now you will go up to the temple of the LORD. 6 I will add fifteen years to your life. And I will deliver you and this city from the hand of the king of Assyria. I will defend this city for my sake and for the sake of my servant David.' " 7 Then Isaiah said, "Prepare a poultice of figs." They did so and applied it to the boil, and he recovered.
This text will not be unfamiliar to some of you. I think this text is pretty much a slam dunk against God's exhaustive foreknowledge. The only respectable explanation I have heard from a believer in God's exhaustive foreknowledge is that there is an unwritten caveat to the "you will not recover" statement, namely that it really should be understood as "you will not recover unless you pray" and, of course, God know that Hez would indeed pray. Fine
Well, this is not what the text says, and adding such a caveat does substantially change the meaning. However, for the sake of argument, let's say that we accept the possibility that some texts need to be subject to such "implied qualifications". This same kind of argument can be used in regard to texts like Psal 139:16:
"Your eyes have seen my unformed substance; And in Your book were all written The days that were ordained for me, When as yet there was not one of them."
What if I were to propose an "implied qualifier" to the effect that "the days were ordained, subject to your following my ways".
I suggest that it is clear that, unless we can find some basis for not reading this 2 Kings text "as she is wrote", then we have here an example of God not exhaustively knowing the future.