Calvinists derive their belief ultimately from a man named John Calvin who had a man executed over theological differences.
John Calvin helped to have Michael Servetus burned at the stake because he did not believe in the Trinity.
Granted, denying the Trinity is heresy, but we shouldn’t kill people over it.
Calvinist’s believe in a 5 point belief system called TULIP (Which is false).
Total Depravity, Unconditional Election, Limited Atonement, Irresistible Grace, and Perseverance of the Saints.
Ultimately the main belief of Calvinism is fatalism in regards to a person’s salvation (Unconditional Election).
The Calvinists believe God is the one who chooses or forces a person to be saved and He chooses others to not be saved.
In Calvinism: Free will of man in choosing salvation does not exist at all in our choice involving God.
Calvinists are confused because there are some verses that sound like Calvinism at first glance (like John 6:44, and Romans 9), but they are not reading these pieces of Scripture in context.
Verses that should end the argument of Calvinism are:
2 Thessalonians 2:10 - The reason why the wicked perish is because they received not the love of the truth that they MIGHT be saved.
Jonah 3 - God tells Jonah judgment is coming for Nineveh in 40 days, and when they forsake their evil ways, that is when God turns back and bringing judgment upon them.
Psalms 7:11 - God is angry at the wicked every day. Note: Why is God angry with them if He chose them to be damned?
Matthew 23:37 - Jesus says that He desire for the people of Jerusalem to be gathered to Him like a hen gathers her chicks, but they would not allow Him to do so.
There is a lot more verses of course, but these are just a couple of the heavy hitter verses that refutes this false belief.