Although Calvin did not create the following himself, the Five Points of Calvinism are easily remembered by the acrostic TULIP:
Total Depravity (Total Inability):
This is the doctrine that affirms the whole corruption of man's nature. According to the Calvinist, every aspect of the being of man is affected through the rebellion of the Fall, so that no one is capable of pleasing God through the efforts of his own natural disposition. According to the doctrine of total depravity, the human person not only cannot please God, but apart from God's effectual grace, no man or woman even has the desire to please Him. Since all sinned in Adam, the representative of all, all are born in sin, and none are innocent, not even infants. All carry the burden of Adam's guilt, since all are in Adam and he is the perfect representative. Since all who come after Adam inherit his guilt, so that everyone is totally depraved, having no natural ability or desire to know or please God, everyone who comes after Adam is also deserving of the hot wrath and punishment of a holy and righteous God.
The idea of total depravity, according to the Calvinist, is not that we all do all the evil we are capable of, but rather, that all parts of our beings are corrupted by sin, and therefore there is nothing in us which can naturally commend us to God.
The Calvinist therefore denies the common doctrine that men naturally hunger to know God, or that men and women naturally desire Him.
Given that "all have sinned and fallen short of the glory of God," which means, according to the Calvinist, that we are all totally depraved, in order to be saved it is necessary for God to initiate salvation. He does this unconditionally, according to his own private desire, choosing whom He will save not according to each one's own merit, nor according to His knowledge of how each one will respond to Him, but rather, according to His own mysterious plan. God's election of those whom He will save is effectual from before the foundation of the world.
Some Calvinists differ on whom will not be saved. Those who teach "double predestination" assert that God also elects whom will be damned, while others assert that God merely overlooks those whom he has not elected to salvation, so that their own natural depravity damns them.
The Calvinst therefore denies the notion of free-will, as well as any idea that God and man works together in synergy in order to accomplish salvation.
Limited Atonement (Particular Redemption):
Since salvation is based solely on the desire and will of God, and not on the will of man, and since God unconditionally elects those whom He saves, while damning others, the atonement is logically therefore limited only to those whom He has elected.
The idea behind the doctrine of limited atonement is that God is absolutely sovereign, accomplishing salvation according to His will and power, not the will not power of man. Therefore, when Christ dies for sin, he dies only for the sins of the elect. It would not make sense for Him to redeem those whom God has chosen to damn, or those whom He has not chosen for salvation. Ergo, the atonement is never non-effectual, but it is totally efficacious, or powerful to save, in the lives of those whom God has elected.
The Calvinist would therefore deny the doctrines which assert that Christ dies for the whole world, including those who reject Him to their own damnation.
Again, undergirding this doctrine is the concept of God's absolute sovereingty, as well as the foregoing doctrines. Since the elect are saved according to the pleasure of God alone, not on the basis of their own merit or choosing; and since God effects this through the atonement which is achieved for the elect alone, God must therefore initiate salvation in the personal lives of the elect.
God does this through His grace, which changed the heart and nature of the elect person prior to conversion. Therefore, the elect person is regenerated (or "born again") prior to his conversion to Christ.
God initiates salvation by working upon the interior deadness of the person's heart and soul, bringing to life the desire to know Him, and as a result, the person whom God chooses in response chooses God. Just as there is no one who would naturally seek to know God, there is also no one who would willingly reject God's effectual grace towards salvation as His Spirit works upon the person's heart. His grace is completely efficacious, regenerating and converting the totally depraved souls of His elect people.
This doctrine is opposed to the idea that God's grace can be resisted, or that men can choose or resist the efficacious grace of God.
Perseverance of the Saints:
Those who are born as children of wrath, corrupt and sinful by nature, yet the elect of God, for whom alone Christ died, and who have experienced the efficacious grace of God leading to regeneration and conversion, will perservere to the end.
As a logical extension of the foregoing, the Calvinist asserts that the elect cannot fall away. His salvation, initiated and secured by Christ, rooted in the absolute sovereignty and power of God, is guaranteed to the end. In the eternal security of God's grace, according to the Calvinist, the elect person will experience the subjective knowledge of his own assurance of salvation.
Therefore, the Calvinist rejects the doctrine that one can be saved, then fall away from grace, or lose his salvation.
This is a summary view of the five points of Calvinism. The underlying theme is that God alone is responsible for every aspect of salvation, from beginning to end, election to glory, and man contributes nothing to it.
Soli Deo Gloria (to God alone be glory) was the cry of Calvin’s heart, and it should be the heart cry of all Christians, for salvation indeed is by grace alone, through faith alone because of Christ alone.
Soli Deo Gloria!