A list-member of greektheology once said:
"I agree with you, there are definite paradoxes with omniscience in correlation with and predestination verses free will. But, with respect to omniscience (in the classic sense) and foreknowledge (which actual is rather redundant); I think that if you have the free will to choose T1 to cut the grass and change your mind to T2; T2 is ultimately your choice. T2 is what would have always been known to God, not T1. Now how does that answer a verse like Luke 10:31? One possibility, that it is the perception of chance. There are instances where God appears to change his mind. But, does the Alpha and the Omega, say one thing and later decide not to follow through? An example could be found in Jonah chapter 3. God tells Jonah again to go to Nineveh but on this time he goes. Jonah tells the people of Nineveh that if they will keep sinning, Nineveh will be destroyed in 40 days. After a little while the whole city became religious and started obeying God. Did God know all along or did he change his mind and spare them? Or is this "change of heart" simply how we understand the incident?"
I have given thoughtful consideration to your question and it is another good one. While I don't want this conversation to stray too far into Hebrew (Scripture) theology, I think we need to address this vital issue.
Initially, I wonder if "chance" is our perception or if its an objective reality. In Eccl. 9:11, Qoheleth writes: "time and chance happeneth to them all" (ASV). This passage indicates that at least some events in our lives happen by "chance." This view also seems to be corroborated by the Scripture in Luke that was referenced heretofore (Luke 10:31). That verse says in part: KATA SUGKURIAN DE hIEREUS TIS KATABAINEN EN THi hODWi. Again, "by chance," the priest happened to be traveling along the road. There is no indication within this pericope that God foreordained the priest's actions. In fact, I actually wonder what purpose would be served by God foreknowing or foreordaining everything. For example, let's say that one day I was driving down the road imbibing a fifth of liquor (MH GENOITO!) and I lost control of my vehicle which led to me hitting a bridge.
Did God foreordain my actions? Were my actions seen long before there was ever a human race? What would have happened if I had not been drinking and driving? Would I have been involved in this horrible accident? Maybe, but it would not have been as a result of driving while intoxicated. In this case, I would put the blame on my present actions. I believe that God would choose not to know whether I would do such a foolhardy thing. At least, that's the way I see it. :-)
Conversely, as I read the OT and NT, I find that chance is possibly modified by God's intervention. A case example is Ruth 2:4: "And she went, and came and gleaned in the fields after the reapers: and her hap was to light on the portion of the field belonging unto Boaz" (ASV).
The writer of this particular OT account states that Ruth happened to "light on the portion of the field belonging unto Boaz." We are thus informed that Ruth coincidentally (fortuitously) began working in the field of Boaz. But the rest of the narrative assures us that God's ENERGEIA is at work in the life of Ruth. Now it is quite possible that God could have used Ruth if she would have lit upon another field belonging to someone else. The fact is, however, that she landed on Boaz's plot of land. Was this mere chance? Was it pure coincidence that Ruth began to work for Boaz? Personally, I think not. At the same time, I don't believe that God foreordained this event before there was ever a Ruth or a Boaz. Similarly, I find it quite implausible that God foreordains every event that happens throughout the KOSMOS. But I am not saying that the account is wrong when it attributes Ruth's fate to chance. My point is that God is also at work in Ruth's life (compare Ecclesiastes 9:1).
Regarding your question about Jonah 3. True, some wish to view the account anthropomorphically. I have reservations about such an approach for the following reasons. The Hebrew word used to describe God's "change of mind" is NaHaM. Concerning this lingual symbol, J.G. Wenham writes:
'"Regret" or "repent" may suggest a change of attitude, but when God "repents," he starts to act differently. Here [Gen. 6:6] and in 1 Sam. 15:11 and Jer. 18:10 he regrets some good thing he has done for his people, whereas in Exod. 32:12, 14; 2 Sam. 24:16; Amos 7:3, 6 he repents of some evil he is carrying out. That God should change his mind might lead to his being accused of capriciousness, which Scripture firmly denies: "God is not a son of man that he should repent" (Num 23:19; Cf. 1 Sam. 15:29). Such remarks obviously raise various questions for the doctrine of divine sovereignty and its correlate human responsibility, but theological systematization is hardly the concern of the biblical narrators. For them divine repentance is a response to man's changes of heart, whether for better or worse" (Wenham, JG. _Genesis_ Waco, Texas: Word, 1987. P. 144).
I concur with Wenham when he writes that God responds to the changes of men, "for better or worse." That is, when God changes, He is simply responding to the actions of his creatures. To illustrate, before I began to exercise faith in Christ as Savior and King, I was one of God's enemies (Rom. 5:8ff); the wrath of God remained upon me (John 3:36). After taking the necessary steps to become reconciled to God, God's attitude toward me changed from one of wrath to one of love and kindness. When God made this change, however, it was not a change of essence: it was a relational change. I would contend that it was an actual, not just a perceptual change. In sum, I think that chance is real, and change in God is real (as explained above)--"accidents" (i.e. things not foreordained) do happen. At the same time, it is important to remember that everything is in the hand of God (Eccl. 9:1ff). Nothing can happen without His permission.