To summarize the key teachings of Calvinism, theologians often refer to the TULIP acronym. This helps us understand the different aspects of Calvinism and Arminianism.
Westminster Confession: “Man by his fall into a state of sin, hath wholly lost all ability of will to any spiritual good accompanying salvation; so as a natural man, being altogether averse from good, and dead in sin, is not able, by his own strength, to convert himself, or to prepare himself thereunto” (Westminster Confession of Faith, 9.3).
Scripture describes humans as evil, deceived, and corrupt (Gen. 6:5; 8:21; Jer. 17:9; Mk. 7:21). Since humans are so evil, they cannot respond to God. Sinners are so depraved that they are unable to “seek for God” (Rom. 3:11-12), and they are spiritually dead (Rom. 5:12; Eph. 2:1-3; Col. 2:13). Just as dead people cannot cause themselves to come to physical life, sinful humans cannot cause themselves to come alive to spiritual life.
Arminian view: Arminians agree that “none seek for God” (Rom. 3:10-12). They agree that no one would come to Christ, unless he was drawn (Jn. 6:44, 65). However, they believe that God is drawing “all men” to himself (Jn. 12:32; 16:8). Therefore, because all men are being drawn through prevenient grace, they have the ability to exercise faith. Arminianism denies that faith is a work, since faith and works are constantly contrasted in the Bible (Rom. 4:4-5; Gal. 2:16).
Westminster Confession: “Those of mankind that are predestined to life, God, before the foundation of the world was laid, according to His eternal and immutable purpose, and the secret counsel of good pleasure of His will, has chosen, in Christ, to everlasting glory, out of His mere free grace and love, without any foresight of faith, or good works, or Perseverance in either of them, or any other thing in the creature, as conditions, or causes moving Him thereunto; and all to the praise of His glorious grace” (Westminster Confession of Faith, 3.5).
Salvation is not dependent on man’s freewill to choose it. If human-generated faith plays a part in salvation, salvation would not be entirely by grace (Eph. 1:4-5; 2:8-9; Rom. 9:16-24). Jesus taught that “all” that the Father gave to him would be raised up on the last day (Jn. 6:37-39). God foreordains those who will come to Christ (Rom. 8:28-33). God has an “elect” people (Mt. 24:22-24, 31; Rom. 11:5), whom he has “chosen” (Eph. 1:4, 11; 1 Thess. 1:4-5; 2 Thess. 2:13; 1 Pet. 1:1-2). God has “appointed” some for eternal life (Acts 13:48). God chooses the elect based on his divine will—not based on anything in the sinner (Rom. 9:11-13, 16). The reason some people do not believe is because they are not those for whom Christ died (Jn. 10:26).
Arminian view: God chooses us “in Christ” (Eph. 1:3-4). Because Jesus was “chosen,” believers are chosen “in Him.” God does give one condition for salvation: faith (Eph. 1:13; Rom. 3:28).
Jesus only died for the sins of the elect—not the entire world. Jesus didn’t try to save us through his atoning death; he actually saved us. Jesus didn’t make salvation possible, but actual. Various passages state that Jesus died for “his sheep” (Jn. 10:11, 14-15), for “his people” (Mt. 1:21), and for “the church of God” (Acts 20:28; Eph. 5:25). Furthermore, as John Owen argued, Christ must have only paid for the sins of the elect. Otherwise, there would be a “double payment” for people who reject Christ’s offer. That is, Jesus paid for their sins, and then, they would pay for their sins as well.
Arminian view: Christ died for the whole human race, even if they reject his offer of salvation (Jn. 1:29; 1 Jn. 2:2; 2 Cor. 5:19; 1 Tim. 4:10; Heb. 2:9; Titus 2:11; Mt. 11:28-29; Acts 17:30; cf. Ps. 145:9).
Westminster Confession: “All those whom God has predestined to life, and those only, He is pleased, in His appointed and accepted time, effectually to call, by His Word and Spirit, out of that state of sin and death, in which they are by nature, to grace and salvation, by Jesus Christ; enlightening their minds spiritually and savingly to understand the things of God, taking away their heart of stone, and giving to them a heart of flesh; renewing their wills, and by His almighty power determining them to that which is good, and effectually drawing them to Jesus Christ; yet so, as they come most freely, being made willing by His grace. This effectual call is of God’s free and special grace alone, not from anything at all foreseen in man, who is altogether passive therein, until, being made alive and renewed by the Holy Spirit, he is thereby enabled to answer this call, and to embrace the grace offered and conveyed in it” (Westminster Confession of Faith, 10.1-2).
Westminster Shorter Catechism: “What is effectual calling? Effectual calling is the work of God’s Spirit, whereby, convincing us of our sin and misery, enlightening our minds in the knowledge of Christ, and renewing our wills, he doth persuade and enable us to embrace Jesus Christ, freely offered to us in the gospel” (Question 31).
Since humans are dead in sin and fully rejecting of God, then God needs to reach them by irresistible grace. God needs to regenerate the person so that they can love, seek, and respond to God’s call in and through the gospel (Deut. 30:6; Ezek. 36:26). The ordo salutis (“order of salvation”) is regeneration and then faith—not faith and then regeneration. God “grants repentance” and “grants faith” to humans (2 Tim. 2:25-26; Phil. 1:29; Eph. 2:8-9; Acts 5:31; 11:18). God “opens” people’s hearts in order to come to faith (Acts 16:14). If God has given certain people to Christ, then they will irresistibly come to Him (Jn. 6:37, 44, 65; Rom. 8:28-32). We are not saved according to our will, but according to God’s will (Jn. 1:12-13; Rom. 9:16).
Arminian view: God desires that all people be saved (1 Tim. 2:4; 2 Pet 3:9; Ezek. 18:23), and he calls and convicts all people (Jn. 1:9; 12:32; 16:8; Mt. 22:14). However, Scripture teaches that humans are capable of resisting God’s will (Mt. 23:37; Heb. 4:2; Lk. 7:29-30). The ordo salutis (“order of salvation”) is faith followed by regeneration (Jn. 3:14-15, 18, 36; 1 Jn. 5:1).
Perseverance of the Saints (or Preservation of the Saints)
Westminster Confession: “They whom God has accepted in His Beloved, effectually called, and sanctified by His Spirit, can neither totally nor finally fall away from the state of grace, but shall certainly persevere therein to the end, and be eternally saved” (Westminster Confession of Faith, 17.1).
Many passages affirm that the believer has eternal security (Jn. 3:36; 5:24; 6:47; 6:51; 11:25; 1 Jn. 5:13; 1 Pet. 1:23). Jesus personally keeps the genuine believer secure (Jn. 6:37, 39; 10:27-30; Rom. 8:29-30, 35-39; 1 Cor. 1:8; Eph. 1:13-14; 4:30; Phil. 1:6; 1 Pet. 1:3-5). Believers need to persevere in faith and good works to “make certain” God’s “calling and choosing” (2 Pet. 1:10; Jn. 14:21; Eph. 2:10; Phil. 2:12-13).
Arminian view: Many Arminians hold that believers can lose their salvation by apostatizing, persisting in heinous sin, or perhaps by returning the gift of salvation through their free will. However, it is neither logically nor biblically necessary for Arminians to reject eternal security. We largely hold to Arminianism, but we also affirm the eternal security of the believer (see “Lordship Theology” and “Eternal Security”).
 John Owen, The Death of Death in the Death of Christ: A Treatise in Which the Whole Controversy about Universal Redemption is Fully Discussed, 1647.
 A. Pink, The Widsom of Arthur W. Pink, vol. 1, Zeeland, Reformed Church, 2009, p. 65. R. C. Sproul, Chosen by God, Carol Stream, Tyndale House, 2011, p. 73. “What We Believe About the Five Points of Calvinism”, desiringgod.org.