I went into both sides and I came across the tension between Calvinism and Arminianism . But I am not what you would call an expert on it by any stretch of the immaginatin, so please feel free to give more insight.
According to Calvinism:
"Salvation is accomplished by the almighty power of the triune God. The Father chose a people, the Son died for them, the Holy Spirit makes Christ's death effective by bringing the elect to faith and repentance, thereby causing them to willingly obey the Gospel. The entire process (election, redemption, regeneration) is the work of God and is by grace alone. Thus God, not man, determines who will be the recipients of the gift of salvation."
Thus they stand against the freewill of man being turned to God on its own as seen in the following statement...
"... and I will go as far as Martin Luther, in that strong assertion of his, where he says, If any man doth ascribe of salvation, even the very least, to the free will of man, he knoweth nothing of grace, and he hath not learnt Jesus Christ aright. It may seem a harsh sentiment; but he who in his soul believes that man does of his own free will turn to God, cannot have been taught of God, for that is one of the first principles taught us when God begins with us, that we have neither will nor power, but that He gives both; that He is Alpha and Omega in the salvation of men." (Charles H. Spurgeon from the sermon Free Will A Slave (1855) referring to Luther's book The Bondage of the Will which is listed with other resources on this topic after this article).
Now Arminianism attempts to explain the relationship between Gods sovereignty and mankinds free will, especially in relation to salvation. While Calvinism emphasizes the sovereignty of God, Arminianism emphasizes the responsibility of man. If Arminianism is broken down into five points, similar to the five points of Calvinism, these would be the five points:
(1) Partial Depravity humanity is tainted by sin, but not to the extent that we cannot chose to come to God on our own. We are capable of choosing to accept salvation or reject it without any influence from God. Note - classical Arminianism rejects "partial depravity" and holds a view very close to Calvinistic "total depravity."
(2) Conditional Election God chose who would be saved based on knowing beforehand who would believe. God chooses those who He knows will believe.
(3) Unlimited Atonement Jesus died for everyone, even those who are not chosen and will not believe. Jesus death was for all of humanity, and anyone can be saved by belief in Him.
(4) Resistible Grace Gods call on a persons life to be saved can be resisted and/or rejected. We can resist Gods pull towards salvation if we choose to.
(5) Conditional Salvation Christians can lose their salvation if they continue in a life of sin and/or fall away from God. The maintenance of salvation is required for a Christian to retain it.
Now some modern Arminians deny "conditional salvation" and instead hold to "eternal security." Now the only point of Arminianism which Calvinists would agree is point #3 Unlimited Atonement as they see as most Christians that the Bible indicates that Jesus died for the sins of everyone in the entire world.
1 John 2:2 says, He is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world.
2 Peter 2:1 says that Jesus even bought the wicked who will reject him such as false prophets who are doomed: But there were also false prophets among the people, just as there will be false teachers among you. They will secretly introduce destructive heresies, even denying the sovereign Lord who bought thembringing swift destruction on themselves. Jesus death and atonement is available to everyone who will believe in Him. Jesus did not just die for those who will be saved but for the whole world, but only those who accept His gift gain eternal life.
Calvinism tends to not agree with the other four points of Arminianism pointin to
Romans 3:10-18 which they feel argues for total depravity and that
Romans 8:28-30 as showing that conditional election underemphasizes Gods sovereignty. Calvinist feel that resistible grace underestimates the power and determination of God and that conditional salvation makes salvation a work rather than a gift of grace
Adventism tends towards the Arminian (Free Will) view and away from Calivinism and this cause some conflict with Calvinist, for those who remember the dialogues initiated with Adventist by evangelicals Donald Barnhouse and Walter Martin, who sought clarification on what Adventists believed. The ones who fought the hardest from accepting Adventist were the Calvinist theologians and church leaders such as evangelical Anthony Hoekema (who felt Adventists were more in agreement with Arminianism), who argued that some Adventist doctrines were heterodox and did his best to keep them from being accepted.