The following information is quoted directly from www.lcms.org/faqs/denominations.
What are the major differences between Lutheran churches and Reformed (or Calvinist) churches?
Just as there are many significant differences in theology and practice between Lutherans of varying denominations, the same is true when it comes to different churches within the Reformed tradition. Differences exist among Reformed churches even regarding such fundamental issues as the authority of Scripture and the nature and centrality of the doctrine of justification.
Historically, however, most Reformed churches adhere to the five points of Calvinist theology commonly summarized by the acrostic “TULIP” as these were set forth at the Synod of Dort (1618-1619). On page 41 in his book, Churches in America, Dr. Thomas Manteufel reviews these five points and explains how they compare and/or contrast with what Lutherans believe regarding these matters.
T (Total Depravity)
The Calvinists rightly teach that all descendants of Adam are by nature totally corrupt in spiritual matters. People do not have freedom of the will to turn to God in faith or cooperate in their conversions (Eph. 2:1; John 3:5-6; Rom. 8:7).
U (Unconditional Predestination)
Scripture does teach that it is by grace that God has predestinated the elect to eternal salvation and given them justifying faith. It is not because of any condition fulfilled by them (2 Tim. 1:9; Eph. 1:4-6; Phil. 1:29). However, the Bible does not teach, as do the Calvinists, that some are predestined for damnation. God wants all to be saved (1 Tim. 2:4).
L (Limited Atonement)
It is true that Christ died for the church and purchased it with His blood (Eph. 5:25; Acts 20:28). Furthermore, His atoning death does not mean that all people are saved (1 Cor. 1:18). However, Jesus died for all (2 Cor. 5:15).
I (Irresistible Grace)
We agree that God makes us alive by His mighty power, without our aid (Eph. 2:5; John 1:13). But Scripture warns we can resist God’s gracious call (Matt. 23:37; Acts 7:51; 2 Cor. 6:1). And some people do resist God’s grace, or all would be saved (1 Tim. 2:4). Furthermore, God warns us not to resist His grace (2 Cor. 6:1; Heb. 4:7).
P (Perseverance in Grace)
We affirm with Scripture that those who are predestined to salvation cannot be lost but will continue by God’s power to a blessed end (Rom. 8:30; 1 Peter 1:5). Scripture does not teach, however, that those who come to faith cannot lose that faith (Heb. 6:4-6; 10:26-29; Ps. 51:11). God urges His people not to continue in sin but to live in repentance and faith (Rom. 6:1-4).
John Calvin must be regarded as the father of Reformed theology and the founder of Presbyterian church polity. The central and controlling thought of Calvinism is Calvin's concept of the glory of God. What must I do for the greater glory of God?
Calvin held to the principle of Scripture alone, sola Scriptura. But this differs from the Lutheran understanding of the term. Lutheran theology asks: What has God done for my salvation? and finds the answer in the Scriptural revelation of God's grace. Calvin asks: What must I do to the greater glory of God? and sees in the Bible the Sovereign's will for man's conduct and belief.
In both Calvinism and Lutheranism the theological slogan is soli Deo gloria [to God be the glory]. But the motivation differs: in Calvinism because man must fear and glorify the sovereign Lord; in Lutheranism, because man is privileged to trust and serve the gracious and forgiving God.
Following his logic, Calvin teaches a limited atonement--Jesus did not die for all people [contrary to John 1.29 for example]. Calvin taught the absolute sovereignty God chooses what disposal He will make of Christ's redemptive work. And God decreed that Christ's death is only for the elect, His people.
For Calvin, repentance, manifest in self-denial and meditation upon the future life, is the ground of the assurance that the believer is in the state of grace and thereby in the possession of a certain sign of his election. The basis of faith is therefore not, as in Lutheran theology, the universal promise of God contained in the Gospel, but the Holy Spirit's activity evident in producing self-denial and observance of the rules for Christian living. The certainty of salvation, for Calvin then, boils down to our works.
Calvin holds that the primary function of the word and sacraments is that of teaching man the will of the sovereign Lord of the universe.
For Calvin, participation in the sacraments is not, like it is in Lutheranism, for the purpose of obtaining the promises of God, but it is a public profession of faith.
In Holy Communion, Calvin viewed the entire act of eating and drinking the physical elements as a symbol of an actual spiritual eating and drinking. He held that since Christ withdrew His body from the earth, the pious souls can be united with the body of Christ only by ascending spiritually through faith to Christ's body which is locally confined in heaven. He rejected the doctrine that in the Person of Christ the divine properties are communicated to Christ according to the human nature. Calvin held, furthermore, that the chasm between the ascended Christ, who is now in the uncreated realm of eternity, and the believers, whose abode is in the finite world, is so infinite that only God Himself can bridge this gulf. According to Calvin, God can close the infinite gap between Himself and man solely through the secret and incomprehensible power of the Holy Spirit. By His immediate working the Holy Spirit becomes the link between Christ and the believer.
For Calvin, then, Jesus is present in Holy Communion--but only spiritually, not physically as Lutheranism teaches [in accord with Scripture]. Lutheranism simply believes Jesus' word "This is My Body and this is My blood" and believes that the communicant is receiving in his/ her mouth Jesus' very body and blood--that very body that was loaded down with the sins of the world on the cross and that very blood that was poured out for our forgiveness. Lutherans do not try to explain the "how" this can be. How comforting to know that Jesus is not "locked away" high, far away in heaven but is with us here and now in the Blessed Sacrament, giving us His very body and blood for the forgiveness of sins and eternal life.
[adapted from: Mayer, F. E., The Religious Bodies of America, St. Louis, MO, Concordia Publishing House, 1961, pp. 197-220]