Here are the four points of the TULIP, in John MacArthur's words, that I believe are unbiblical.
“Total depravity” means you can’t do anything to save yourself. You can’t even make a right choice. You can’t awaken your spiritual deadness. You can’t give life where there is death. You can’t come to a right conclusion on your own. Total depravity means that everyone, is by virtue of their own will and their own power and their own choices, incapable of redemption. That’s total depravity.”
This statement is almost biblical, only the “bolded” sentences are unbiblical. God sets before us the choice between life and death, and therefore to say we are unable to choose life contradicts scripture. To avoid the obvious contradiction, Calvinists say when you choose the only choice available, death, you are actually making a “choice.” But that redefines “choice” to mean “non-choice.” Jesus teaches in Matthew 13:20-22 that some men who are dead in their trespasses and sins received the gospel with joy, certainly the right choice. Therefore the "T" in the Tulip is unbiblical if it is asserted to apply to all men.
“In the case of “Unconditional election”, you have the view in the Scripture that the people who are saved are saved because they were chosen by God apart from any merit of their own, apart from any condition.”
This statement is completely unbiblical, James 2:5 tells us God chooses people based on their condition, those rich in faith, those that love God, and those who do not treasure the things of this world. Paul teaches a similar truth in 1 Corinthians 1:26-31. And again, Paul teaches that God chooses people in his day, just as God chose people who were faithful in Romans 11:3-6. John 3:16 says whoever believes in Him shall not perish.
“Limited atonement”, in the typical reformed view, means that the atonement, in its actual work, the actual efficacy of the atonement, was only for the elect.”
Again, this statement is completely unbiblical, 1 John 2:2 tells us that Christ became the propitiation (means of salvation) not only for us (members of the Church) but also for the whole world. Paul tells us He laid down His life as a ransom for all. Therefore the finished work of the cross provides (1) the means of salvation available to all men, and (2) provides salvation for anyone spiritually placed in Christ.
“Irresistible grace”, which is the idea that when the spirit of God works on the heart of a sinner, the sinner can’t resist.”
And finally, this too, is almost biblical. But it is carefully crafted to blend the idea that God's will, what ever it is, cannot be resisted, with the false idea that God's will is to compel people with Irresistible Grace to trust in Christ. However, in Matthew 23:13 men who are entering, or trying to enter the Kingdom of Yahweh, and therefore could not be turned aside because of irresistible grace if the premise were true, are turned aside and do not enter. Therefore it is God's will to allow men to accept or reject the gospel and not compel them as Calvinism wrongly asserts.
Indeed the idea of universal grace i.e. the grace of God that brings salvation has appeared to all men, is in Scripture, but IMO it is often misunderstood.
There is a difference between appearing to all men and being received by all men. I frequently hear that God would not give us commands and would not have given us the choice between life and death in futility. In other words the common perception is that Calvinism posits that the choices God gives us in Scripture are illusory, which draws the ire of the broader Christian world.
However, this is exactly what God has done throughout Biblical history. God knew Israel would break covenant with Him long before they began bowing to other gods. We know because He tells us this in no uncertain terms. So effectively God gave His people commands He knew they would disobey.
Many others posit God would not create people merely for condemnation, however, this ignores verses like Proverbs Chap. 16 verse 4.
The message of atonement has appeared before all men. In other words the message of Christ is available to all even though God knows not all will receive it. Indeed even the persuasion of the Holy Spirit is resisted by men, as we see in Acts chap. 7 verse 51. Christ ministered to those who rejected His message. These aspects of grace are not denied to all people, however, they will only be received by the elect. Not only does Scripture testify to this, human history confirms it as well.
Now many will say yes this is true, but God really looked down the tunnel of time to see who resisted and who obeyed. However, is this what saved by grace means? Aren't we told that our own efforts, will power, desires, etc. have no place in the economy of salvation? That we are formed by God like a potter forms his clay?
The elect were foreknown by God in a real sense, like we see with Jeremiah (chap. 1 verse 5) We were formed in the womb, like an engineer builds a machine. We can no sooner resist grace than a machine designed to produce rolls of paper can fly.
Passages such as Ephesian chap. 1 verses 4-5 confirm we were predestined for adoption before the founding of the world. In the Gospel of John chap. 3 verse 18 we learn that those who do not believe, are not only condemned but condemned "already" (a past tense event).
The problem with many people's views on Calvin is in the first instance an erroneous understanding of what Calvin actually taught (even some Calvinists don't quite understand his teachings all that well).
Many Calvinists will say, for example, that in many cases where the word "all" is used it does not mean "all" in the natural sense; rather it only applies to the elect. This is true in certain cases, however, I've seen cases where the context demands that "all" mean "all" in the natural sense, where a Calvinist would say it does not (and thereby shoot our soteriology in the foot). They don't understand the notions the effectual calling and common grace (or reject the idea of common grace outright).
Many are called but few are chosen. Does this mean everyone is called? Paul tells us in Romans chap. 10 verse 16 that people cannot believe if they never hear the word, and can only hear if someone preaches to them. Millions, perhaps billions have lived and died without ever hearing the Gospel message. Arminians will say that somehow they did hear the Gospel message, or go through theological gymnastics to affirm their faulty idea that all aspects of grace are imputed to mankind universally. The idea smacks against logic, and our own human history testifies to the error of this presumption.
However, remember those ancient Hebrews, who spent 40 years in the desert, but many still would up disobeying God and drawing His condemnation. God foretold that they would do this & of course they did. He was in their midst during this entire period, His grace was all around them, yet they resisted as they were destined to do. In the end the prophets and only 7,000 who did not bow to baal were kept by God.
So all of these people were "called" but only few were ultimately chosen. You will say how is that anyone can resist God's will? But who are we to say to the potter why have you formed me like this? Doesn't the potter have the right to make one lump for honorable use and the other for reprobation? Indeed He does and He did.