"An example of the debatable Bible verses is 1 Samuel 15:11 ""I greatly regret that I have set up Saul as king, for he has turned back from following Me, and has not performed My commandments." Here it seems that God did not have perfect foreknowledge because of Saul's free will. .."~Razorism
"Incommunicable Attributes of God" by Wayne Grudem - excerpts:
"God's unchangeableness is defined as follows:
'God is unchanging in his being, perfections, purposes, and promises, yet
God does act, and he acts differently in response to different situations.'
The second half of that sentence guards against the idea that
unchangeableness means inability to act at all.
Does God sometimes change his mind?
"Yet when we talk about God being unchanging in his purposes, we may wonder
about places in Scripture where God said he would judge his people and then
because of prayer or the people's repentance (or both) God relented and did
not bring judgement as he had said he would.
Examples of such withdrawing from threatened judgement include the
successful intervention of Moses in prayer to prevent the destruction of
the people of Isreal [Ex.32:9-14], the adding of another 15 years to the
life of Hezekiah [Isa.38:1-6], or the failure to bring promised judgement
upon Nineveh when the people repented [Jonah 3:4,10].
Are these not cases where God's purposes in fact did change?
Then there are other passages where God is said to be sorry that he had
carried out some previous action. One thinks of God being sorry that he
had made man upon the earth [Gen.6:6], or sorry that he had made Saul king
[1 Sam.15:10].
Did not God's purposes change in these cases?
These instances should all be understood as true expressions of God's
*present* attitude or intention *with respect to the situation as it exists
at that moment*.
If the situation changes, then of course God's attitude or expression of
intention will also change. This is just saying that God *responds
differently to different situations*.
The example of Jonah preaching to Nineveh is helpful here. God sees the
wickedness of Nineveh and sends Jonah to proclaim, 'Yet forty days, and
Nineveh shall be overthrown!" [Jonah 3:4].
The possibility that God would withhold judgement if the people repented is
not explicitly mentioned in Jonah's proclamation as recorded in Scripture,
but it is of course *implicit* in that warning: the *purpose* for
proclaiming a warning is to bring about repentance. Once the people
repented, the situation was different, and God responded differently to
that changed situation:
'When God saw what they did, how they turned from their evil way, God
repented of the evil which he had said that he would do to them; and he did
not do it.' [Jonah 3:10].
The situations with Hezekiah and with the intercession of Moses are
similar: God had said that he would send judgement, and that was a true
declaration, *provided that the situation remained the same*.
But then the situation changed: someone started to pray earnestly (Moses
in one case, Hezekiah in the other).
Here prayer itself was part of the new situation and was in fact what
changed the situation.
God responded to that changed situation by answering the prayer and
withholding judgement.
In the cases of God being sorry that he had made man, or that he had made
Saul king, these too can be understood as *expressions of God's present
displeasure* toward the sinfulness of man.
In neither case is the language strong enough to require us to think that
if God could start again and act differently, he would in fact not create
man or not make Saul king.
It can instead imply that God's previous action led to events that in the
short term caused him sorrow, but that nonetheless in the long term would
ultimately achieve his good purposes. This is somewhat analogous to a
human father who allows his child to embark on a course he knows will bring
much sorrow, both to the parent and to the child, but who allows it
nonetheless, because he knows that greater long-term good will come of it."
[end of excerpts]
Source: Systematic Theology - Excerpted quotes from pages 160, 164-165 of Chapter
11 "Incommunicable Attributes of God" by Wayne Grudem. (Much more can be
found there on the subject)