I have been asked this question so many times. If one is predestined to be damned or to be accepted into heaven, then how can one have free will? Here I will try to share what I have learned from God about predestiny and free will.
Free will is the ability to chose to do, say or to not do or say something. Predestiny is the chosen out come and/or the out come that will be. God knows all thing, can do all things and give man free will. God knowing all thing does not take away from free will. God knows(all knowing)who does, has, and will chose His plan for redemption(Jesus)out of their own free will, thus making them predestined to be in His family and priesthood and co-heirs to the Kingdom of God.
Likewise, God also knows who will, out of their own free will and has chosen not to be apart of His plan for redemption, thus making them predestined for total eternal seperation from the will and love of God.
God's ability to know the out come of one's life and the out come of the world in no way effects man's free will. God knows what we will do, say and how we will act at any given time, but we are free to chose to or not to do or say anything at any given time. It just means that God is all knowing.
Can God's ability to know all things effect a person's free will? Yes. If a person has chosen to give his or her's life to God then God can and will affect the free will of that person, who is about to do and or say something that is not in God's will. As in if someone who has chosen God are about to say or do something to another person, God has been known to change the desire one has to do or say something that is out of the will of God.
Can God's ability to know all things change reality? Yes, God has been know to change the reality of an action that is out of the will of God, for a person(s) who God know has or will give themselves over to the will of God.
Then what is predestination? It is the out come of an event. When, how, and where one dies is known to God, just as the time and date the world will end and the second coming of the Christ is already set, that is predestination. Whether or not one will chose the redemption plan go has put in place is known to God, but the choice to reject or accept His plan is ours.
In conclusion, God knows who will accept His offer of redemption, past, present, and future, and what kind of interaction with God it will take to prove God is real to that person, and who will not accept God's offer for redemption. The one's God knows will accept God's offer are predestined for heaven and the one's who will not accept are predestined for hell, but the choice to accept is up to the individual. Hell was set up FOR the people who will not accept God's offer of redemption. In the Bile Jesus has told His students that they were chosen out of the world (John 15:16-19), and if one reads the first four books of the new testement carefully and looks for this, they will see that Jesus actually went TO the people He had chosen to be His disciples. Also after he chose His disciples people would hear about the power Jesus had and come to Him for help in some kind of way, would stay for some period of time and then would leave. Just as with Moses, King david, Samson, Samuel, Ezekiel, Nehemiah, Mary, and Joseph, God has chosen people out of the world to do His will. What guildlines did God us to chose them? I believe that God knew something about them that man can not see. The will to accept God and His plan for redemption. To make my point in the book of Titus 1:1 it says that Paul is writing a letter for the faith of God's ELECT. Just to clearify so that there is no confusion, God has elected people to also share His love and offer and those that accept it from those people as an offer from God ARE also elected because God knew they would or will accept it, and has chosen to made the offer for every person that would and or will accept it.