Calvinists often take refuge behind the curtains of “God’s ways are higher than our ways” and “it’s a mystery!” whenever they are faced with Bible contradictions, but if they would just start accepting the fact that man has free will, and that God’s will doesn’t always happen (which doesn’t reduce his sovereignty) then all their contradictions would disappear at once. In order to be consistent with calvinism, one must believe that even evil happens according to Gods will, whereas freewillers believe that evil is merely allowed by God and always happens against his will.

Plainly it was God’s will that sin should enter this world, otherwise it would not have, for nothing happens except what God has eternally decreed. Moreover, there was more than a simple permission, for God only permits things that fulfill his purpose./-A.W. Pink, The Sovereignty of God, 2009, 162

So when I say that everything that exists — including evil — is ordained by an infinitely holy and all-wise God to make the glory of Christ shine more brightly, I mean that, one way or the other, God sees to it that all things serve to glorify his Son.”/ John Piper, Spectacular Sins: And Their Global Purpose in the Glory of Christ, 44

God is able without blameworthy ‘tempting’ to see to it that a person does what God ordains for him to do even if it involves evil./ John Piper,  Spectacular Sins: And Their Global Purpose in the Glory of Christ, 24

Moral evil we usually refer to as sin: murder, lying, adultery, stealing, all the ways that people fail to love each other. So what we are considering here is that God rules the world in such a way that all calamities and all sin remain in his ultimate control and therefore within his ultimate DESIGN and PURPOSE. / John Piper on his website 1 July 1998

The death of Jesus offers another example of how God’s sovereign will ORDAINS that a SINFUL ACT COME TO PASS  /John Piper on his website 1 July 1998These specific examples (which could be multiplied by many more instances) where God purposefully GOVERNS the sinful choices of people are generalized in several passages. — Therefore I conclude with [Jonathan] Edwards, “God decrees all things, even all sins.” /John Piper

God may hate a thing as it is in itself, and considered simply as evil, and yet . . . it may be his will it should come to pass, considering all consequences. . . . God doesn’t will sin as sin or for the sake of anything evil; though it be his pleasure so to order things, that he permitting, sin will come to pass; for the sake of the great good that by his disposal shall be the consequence. His willing to order things so that evil should come to pass, for the sake of the contrary good, is no argument that he doesn’t hate evil, as evil: and if so, then it is no reason why he may not reasonably forbid evil as evil, and punish it as such. /  The Works of Jonathan Edwards, A.M.: With an Essay on His Genius …, Volym 2

So evil is necessary, in order to the highest happiness of the creature, and the completeness of that communication of God, for which he made the world; because the creature’s happiness consists in the knowledge of God, and the sense of his love. And if the knowledge of him be imperfect, the happiness of the creature must be proportionably imperfect. / The Works of Jonathan Edwards, A.M.: With an Essay on His Genius …, Volym 2

We sin out of a kind of MORAL NECESSITY because we act according to our fallen nature./ R.C. Sproul, What is Reformed Theology?: Understanding the Basics‎

God wills all things that come to pass…God desired for man to fall into sin. I am not accusing God of sinning; I am suggesting that God created sin. / R.C. Sproul, Jr. Almighty Over All 

If there is one single molecule in this universe running around loose, totally free of God’s sovereignty, then we have no guarantee that a single promise of God will ever be fulfilled. / R.C. Sproul.

I wish very frankly and pointedly to assert that if a man gets drunk and shoots his family, it was the will of God that he should do it…”+ Let it be unequivocally said that this view certainly makes God the cause of sin… / Gordon Clark, Religion, Reason, and Revelation, (Philadelphia, PA: Presbyterian & Reformed), 1961, 221

Sin is one of the ‘whatsoevers’ that have ‘come to pass’, all of which are ‘ordained’…Nothing comes to pass contrary to His decree. Nothing happens by chance.Even moral evil, which He abhors and forbids, occurs by the determinate counsel and foreknowledge of God… man’s inability to explain how God can make things certain, but not compulsory… is no reason to deny that [God] can do it or that he has done it./ W.G.T. Shedd, Calvinism: Pure and Mixed, 32-33, 38-39

Foreordination means God’s sovereign plan, whereby He decides all that is to happen in the entire universe. Nothing in this world happens by chance. God is in back of everything. He decides and causes all things to happen that do happen. He is not sitting on the sidelines wondering and perhaps fearing what is going to happen next. No, He has foreordained everything ‘after the counsel of his will’ (Eph. 1:11): the moving of a finger, the beating of a heart, the laughter of a girl, the mistake of a typist –even sin…Although sin and unbelief are contrary to what God commands…God has included them in his sovereign decree (ordained them, caused them to certainly come to pass) / Edwin. H. Palmer, The Five Points of Calvinism, 24-25

Yes, someone says, but can’t Christians put themselves outside God’s grace? What about those who commit ABOMINABLE SINS? Don’t they nullify the work of redemption in themselves? Don’t they forfeit the love of God? CERTAINLY NOT …. it’s preposterous to think that we can forfeit it [salvation] BY ANYTHING WE DO / John MacArthur, The God Who Loves: He Will Do Whatever It Takes To Draw Us To Him

God controls everything that is and everything that happens. There is not one thing that happens that he has not actively decreed – not even a single thought in the mind of man. Since this is true, it follows that God has decreed the existence of evil, he has not merely permitted it, as if anything can originate and happen apart from his will and power. Since we have shown that no creature can make completely independent decisions, evil could never have started without God’s active decree, and it cannot continue for one moment longer apart from God’s will. God decreed evil ultimately for his own glory, although it is not necessary to know or to state this reason to defend Christianity from the problem evil. / Vincent Cheung – Problem of evil 

Those who see that it is impossible to altogether disassociate God from the origination and continuation of evil nevertheless try to distance God from evil by saying that God merely “permits” evil, and that he does not cause any of it. However, since Scripture itself states that God actively decrees everything, and that nothing can happen apart from his will and power, it makes no sense to say that he merely permits something –nothing happens by God’s mere permission. / Vincent Cheung – Problem of evil 

Here they have recourse to the distinction between will and permission. By this they would maintain that the wicked perish because God permits it, not because he so wills. But why shall we say “permission” unless it is because God so wills? Still, it is not in itself likely that man brought destruction upon himself through himself, by God’s mere permission and without any ordaining. As if God did not establish the condition in which he wills the chief of his creatures to be! I shall not hesitate, then, simply to confess with Augustine that “the will of God is the necessity of things,” and that what he has willed will of necessity come to pass. / John Calvin, Calvin’s Institutes (III, xxiii, 8 & II, iv., 3)

Once again, if it was Christ’s intention to save all men, how deplorably has He been disappointed, for we have His own testimony that there is a lake which burneth with fire and brimstone, and into that pit of woe have been cast some of the very persons who, according to the theory of universal redemption, were bought with His blood. That seems to me a conception a thousand times more repulsive than any of those consequences which are said to be associated with the Calvinistic and Christian doctrine of special and particular redemption. To think that my Saviour died for men who were or are in hell, seems a supposition too horrible for me to entertain. To imagine for a moment that He was the Substitute for all the sons of men, and that God, having first punished the Substitute, afterwards punished the sinners themselves, seems to conflict with all my ideas of Divine justice. That Christ should offer an atonement and satisfaction for the sins of all men, and that afterwards some of those very men should be punished for the sins for which Christ had already atoned, appears to me to be the most monstrous iniquity that could ever have been imputed to Saturn, to Janus, to the goddess of the Thugs, or to the most diabolical heathen deities. / Charles H. Spurgeon

Can a person be saved if he/she refuses to believe in the true gospel but rather believes in heresies? If Spurgeon is correct here, only calvinists can be saved:

And what is the heresy of Arminianism but the addition of something to the work of the Redeemer? Every heresy, if brought to the touchstone, will discover itself here. I have my own private opinion that there is no such thing as preaching Christ and Him crucified,unless we preach what nowadays is called Calvinism. It is a nickname to call it Calvinism; Calvinism is the gospel, and nothing else / The Autobiography of Charles H. Spurgeon, Curts and Jennings, Cincinnati – Chicago – St. Louis, 1898, Vol. I., Page 172.

“Some of the sermons on sex were R-rated, and we gave warnings to parents and sometimes saw whole visiting youth groups walk out blushing halfway through the sermon.  On other occasions, people walked out during the sermon and flipped me off on their way out, a trend that has continued.”  /Mark Driscoll (Confessions of a Reformission Rev. p.134)

“Pastor James continues to lead our monthly film and theology class, at which attendance rises to more than two hundred people depending on the film.  He continues to show an occasional unedited R-rated movie to train our people to think critically about the themes preached through film, which is the new cultural form of preaching.”  / Mark Driscoll  (Confessions of a Reformission Rev., p.157)

“This season [at church] was messy and I sinned and cussed a lot, but God somehow drew a straight line with my crooked Philistine stick.” / Mark Driscoll  (Confessions of a Reformission Rev p.130)

I do believe God does cause people to think they are saved just to damn them but to call that grace is crazy. / a Calvinist

Also free-willers can of course be in error about sin, even if it’s not built into their doctrine by necessity the way calvinism is (I’m not claiming that calvinists therefore sin more than others, but I’m talking about the necessary outcome of their doctrines IF they want to be consistent with what they teach):

Paul wrote most of his epistles to correct error in the church. But he doesn’t say that even the most carnal Corinthians are not saved. /Dave Hunt The Berean Call, January 2007, p. 5.)

Some of you are weak and sickly and some of you sleep. Some of you died because God just brought judgment upon you for the way you have conducted yourselves … there are some sins that are so heinous … and God takes them home for that./ Dave Hunt