The doctrine of free will much too boldly declares that God is not sovereign in all things and that He has no control over a person's salvation. It wrongly implies instead that man is sovereign - all we have to do to be saved is to accept God's gift. And if this be the case (that it's our choice and ours alone, which happens to point to a "works" salvation), why would Jesus have died on the cross for our sins? And if God wouldn't have sent His son to pay our debt, salvation would be worthless. Doesn't make much sense, now does it?
In a certain sense, we do have our own part to play, but it's certainly not us by our own little sinful selves that this is accomplished. If we are the elect of God, He will draw us to Himself through His irresistible grace. So, it's almost like we do nothing at all, it's all Him. If He didn't draw us, we wouldn't accept or cry out for forgiveness of sins.
Everything works according to God's will (Romans 8:28). He didn't choose the elect because He foresaw that they would believe. If this were the case, God would have no control over who would be saved and who wouldn't, and thus, God's will would not be done in this case. He chose them because He wanted to; it was His will to predestine some to eternal glory and others to eternal damnation. If someone is predestined by God to damnation, they can not change this simply by saying that they will believe in Him.
Also, if we have free will and God has no say in the matter, we could choose not to be saved after we've already been saved. We should be able to choose to do this, according to the doctrine of free will. But this is not so. The Bible says in John 10:27-29: "My sheep hear my voice, and I know them, and they follow me: And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand. My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand."
I found some short paragraphs by a one Matthew J. Slick online about the 5 points of Calvinism, which, if you're a free will-er, you probably tend not to believe:
Sin has affected all parts of man. The heart, emotions, will, mind, and body are all affected by sin. We are completely sinful. We are not as sinful as we could be, but we are completely affected by sin.
The doctrine of Total Depravity is derived from scriptures that reveal human character: Man’s heart is evil (Mark 7:21-23) and sick (Jer. 17:9). Man is a slave of sin (Rom. 6:20). He does not seek for God (Rom. 3:10-12). He cannot understand spiritual things (1 Cor. 2:14). He is at enmity with God (Eph. 2:15). And, is by nature a child of wrath (Eph. 2:3). The Calvinist asks the question, "In light of the scriptures that declare man’s true nature as being utterly lost and incapable, how is it possible for anyone to choose or desire God?" The answer is, "He cannot. Therefore God must predestine."
Calvinism also maintains that because of our fallen nature we are born again not by our own will but God’s will (John 1:12-13); God grants that we believe (Phil. 1:29); faith is the work of God (John 6:28-29); God appoints people to believe (Acts 13:48); and God predestines (Eph. 1:1-11; Rom. 8:29; 9:9-23).
God does not base His election on anything He sees in the individual. He chooses the elect according to the kind intention of His will (Eph. 1:4-8; Rom. 9:11) without any consideration of merit within the individual. Nor does God look into the future to see who would pick Him. Also, as some are elected into salvation, others are not (Rom. 9:15, 21).
Jesus died only for the elect. Though Jesus’ sacrifice was sufficient for all, it was not efficacious for all. Jesus only bore the sins of the elect. Support for this position is drawn from such scriptures as Matt. 26:28 where Jesus died for ‘many'; John 10:11,15 which say that Jesus died for the sheep (not the goats, per Matt. 25:32-33); John 17:9 where Jesus in prayer interceded for the ones given Him, not those of the entire world; Acts 20:28 and Eph. 5:25-27 which state that the Church was purchased by Christ, not all people; and Isaiah 53:12 which is a prophecy of Jesus’ crucifixion where he would bear the sins of many (not all).
When God calls his elect into salvation, they cannot resist. God offers to all people the gospel message. This is called the external call. But to the elect, God extends an internal call and it cannot be resisted. This call is by the Holy Spirit who works in the hearts and minds of the elect to bring them to repentance and regeneration whereby they willingly and freely come to God. Some of the verses used in support of this teaching are Romans 9:16 where it says that "it is not of him who wills nor of him who runs, but of God who has mercy"; Philippians 2:12-13 where God is said to be the one working salvation in the individual; John 6:28-29 where faith is declared to be the work of God; Acts 13:48 where God appoints people to believe; and John 1:12-13 where being born again is not by man’s will, but by God’s.
Perseverance of the Saints:
You cannot lose your salvation. Because the Father has elected, the Son has redeemed, and the Holy Spirit has applied salvation, those thus saved are eternally secure. They are eternally secure in Christ. Some of the verses for this position are John 10:27-28 where Jesus said His sheep will never perish; John 6:47 where salvation is described as everlasting life; Romans 8:1 where it is said we have passed out of judgment; 1 Corinthians 10:13 where God promises to never let us be tempted beyond what we can handle; and Phil. 1:6 where God is the one being faithful to perfect us until the day of Jesus’ return."
But how can these passages be refuted? If you believe in the free will of man and not the sovereignty of God, how do you explain these verses? And if you can't, why would you go one believing and preaching that man is more powerful than God?
And we know that all things work together for good to them that love God,
to them who are the called according to his purpose.
For whom he did foreknow, he also did predestinate to be conformed to the image of his Son,
that he might be the firstborn among many brethren.
Moreover whom he did predestinate, them he also called:
and whom he called, them he also justified:
and whom he justified, them he also glorified.