Reformed theology is biblical, and free-willer theology is NOT. Their claim of decisional regeneration is ridiculous and boastful. They say, the unsaved man, with a heart of stone, must produce faith and repentance from it, in order to receive a heart of flesh. Scripture says otherwise...God gives the man a heart of flesh to replace his stony, hard heart, and from this heart issues forth faith and repentance. This is called regeneration, or being born again. The saved man is joined with Jesus, and he begins to bear spiritual fruit as a result. Additionally, many free-willers claim salvation can be lost, which implies that God can fail in his work of salvation. Again, this is a free-willer falsehood which is contradicted by the Scriptures below.
Their claim is boastful, and places too much faith in fallen man's stony, hard heart. God doesn't share his glory in salvation with anyone, and especially not the person themselves!
There is a strong association between dispensationalism and free-willer theology. Many dispensationalists claim that the New Covenant is not for Christians, but is only for the physical nation of Israel.
The fundamental problem with Dispensationalism is their denial of the full ramifications of the fact that the believer is a spiritual descendant of Abraham through being united with Christ through faith. Jesus shares all his inheritance as a descendant of Abraham with them, because they are united with Jesus, his one obedient offspring. The Church is spiritual Israel, as a result of this union, and they share the entire new creation with Abraham.
There are also many other behavioral issues with dispensationalists such as claiming others are spiritualizing or allegorizing Scripture (if they disagree with Dispensationalism), or labeling others as anti-Semites. It is a very divisive theology. They will deny that many of the Scriptures below actually apply to believers in their claim to "rightly divide the Word", instead claiming they only apply to Israel.
SCRIPTURES
Ezekiel 36:25-28 25 I will sprinkle clean water on you, and you shall be clean from all your uncleannesses, and from all your idols I will cleanse you. 26 And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. 27 And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules. 28 You shall dwell in the land that I gave to your fathers, and you shall be my people, and I will be your God.
John 6:35-40 35 Jesus said to them, “I am the bread of life; whoever comes to me shall not hunger, and whoever believes in me shall never thirst. 36 But I said to you that you have seen me and yet do not believe. 37 All that the Father gives me will come to me, and whoever comes to me I will never cast out. 38 For I have come down from heaven, not to do my own will but the will of him who sent me. 39 And this is the will of him who sent me, that I should lose nothing of all that he has given me, but raise it up on the last day. 40 For this is the will of my Father, that everyone who looks on the Son and believes in him should have eternal life, and I will raise him up on the last day.”
John 10:25-29 25 Jesus answered them, “I told you, and you do not believe. The works that I do in my Father's name bear witness about me, 26 but you do not believe because you are not among my sheep. 27 My sheep hear my voice, and I know them, and they follow me. 28 I give them eternal life, and they will never perish, and no one will snatch them out of my hand. 29 My Father, who has given them to me, is greater than all, and no one is able to snatch them out of the Father's hand.
Romans 4:13-16 13 For the promise to Abraham and his offspring that he would be heir of the world did not come through the law but through the righteousness of faith. 14 For if it is the adherents of the law who are to be the heirs, faith is null and the promise is void. 15 For the law brings wrath, but where there is no law there is no transgression. 16 That is why it depends on faith, in order that the promise may rest on grace and be guaranteed to all his offspring—not only to the adherent of the law but also to the one who shares the faith of Abraham
Romans 8:27-30 28 And we know that for those who love God all things work together for good, for those who are called according to his purpose. 29 For those whom he foreknew he also predestined to be conformed to the image of his Son, in order that he might be the firstborn among many brothers. 30 And those whom he predestined he also called, and those whom he called he also justified, and those whom he justified he also glorified.
Galatians 3:16 16 Now the promises were made to Abraham and to his offspring. It does not say, “And to offsprings,” referring to many, but referring to one, “And to your offspring,” who is Christ.
Galatians 3:26-29 for in Christ Jesus you are all sons of God, through faith. 27 For as many of you as were baptized into Christ have put on Christ. 28 There is neither Jew nor Greek, there is neither slave nor free, there is no male and female, for you are all one in Christ Jesus. 29 And if you are Christ's, then you are Abraham's offspring, heirs according to promise
Ephesians 2:1-10 1 And you were dead in the trespasses and sins 2 in which you once walked, following the course of this world, following the prince of the power of the air, the spirit that is now at work in the sons of disobedience— 3 among whom we all once lived in the passions of our flesh, carrying out the desires of the body and the mind, and were by nature children of wrath, like the rest of mankind. 4 But God, being rich in mercy, because of the great love with which he loved us, 5 even when we were dead in our trespasses, made us alive together with Christ—by grace you have been saved— 6 and raised us up with him and seated us with him in the heavenly places in Christ Jesus, 7 so that in the coming ages he might show the immeasurable riches of his grace in kindness toward us in Christ Jesus. 8 For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, 9 not a result of works, so that no one may boast. 10 For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.
Ephesians 2:11-19 11 Therefore remember that at one time you Gentiles in the flesh, called “the uncircumcision” by what is called the circumcision, which is made in the flesh by hands— 12 remember that you were at that time separated from Christ, alienated from the commonwealth of Israel and strangers to the covenants of promise, having no hope and without God in the world. 13 But now in Christ Jesus you who once were far off have been brought near by the blood of Christ. 14 For he himself is our peace, who has made us both one and has broken down in his flesh the dividing wall of hostility 15 by abolishing the law of commandments expressed in ordinances, that he might create in himself one new man in place of the two, so making peace, 16 and might reconcile us both to God in one body through the cross, thereby killing the hostility. 17 And he came and preached peace to you who were far off and peace to those who were near. 18 For through him we both have access in one Spirit to the Father. 19 So then you are no longer strangers and aliens, but you are fellow citizens with the saints and members of the household of God
1 Corinthians 1:26-31 26 For consider your calling, brothers: not many of you were wise according to worldly standards, not many were powerful, not many were of noble birth. 27 But God chose what is foolish in the world to shame the wise; God chose what is weak in the world to shame the strong; 28 God chose what is low and despised in the world, even things that are not, to bring to nothing things that are, 29 so that no human being might boast in the presence of God. 30 And because of him you are in Christ Jesus, who became to us wisdom from God, righteousness and sanctification and redemption, 31 so that, as it is written, “Let the one who boasts, boast in the Lord.”