I would like to direct you to an article by Ashley Evan's at https://biblereasons.com/what-is-calvinism/
Calvinism did not start with John Calvin. This soteriological view is named after him because he is best remembered for his plethora of writings on this theological subject. He followed what was Augustinianism, which was the soteriological understanding of the church historically – all the way back to the apostles themselves.
In evangelical circles, there is a tremendous amount of misunderstanding about the beliefs held dear to the Calvinists. Just like with many denominations, there can be some variation between churches. Just like the Southern Baptist Denomination does not hold to the hate filled teaching of the extremists like Westboro Baptist Church, there are extreme versions of Calvinism (called Hyper Calvinism) to which regular Calvinists would vehemently disagree with.
“It is no novelty, then, that I am preaching; no new doctrine. I love to proclaim these strong old doctrines, that are called by nickname Calvinism, but which are surely and verily the revealed truth of God as it is in Christ Jesus.” Charles Spurgeon
“If anyone should ask me what I mean by a Calvinist, I should reply, “He is one who says, Salvation is of the Lord.” I cannot find in Scripture any other doctrine than this. It is the essence of the Bible.”
“Calvinism is the consistent endeavor to acknowledge the Creator as the Lord, working all things after the counsel of His will.” J. I. Packer
