Justification by faith can easily be identified as the central doctrine during the Reformation because of how it ignited a movement that led to the birth of Protestantism. But as one studies the doctrines that were developed during this pivotal time in the history of the church, it becomes apparent that the doctrine of union with Christ stands out as the central doctrine of Reformed theology. Michael Horton notes:
In effectual calling the Spirit grants us faith in Christ as he is clothed in his gospel. Through this faith we are united to Christ with all of his benefits, as beneficiaries not only of his gifts but of the Giver himself. Chosen in Christ and redeemed in Christ, we are united to Christ by the Spirit through faith. We identify this wonderful reality as union with Christ.
In this article, I aim to explain the believer’s justification, sanctification, and glorification within the concept of union with Christ. I will also show what the Bible and historical figures have to say about union with Christ and provide some practical applications for ministry.
- Justification within the concept of union with Christ
The doctrine of justification has been a source of joy for Christians who believe that they have been declared righteous by God because of their faith in Jesus Christ (Gal 2:16). While this is good and true, there seems to be some misunderstanding surrounding this doctrine. Some see justification simply as a past event that does not have any impact on the way they behave and think as believers. Hence, to correct this misconception, one has to understand justification within the concept of union with Christ. Martin Luther saw the inseparable connection between the doctrine of justification and the believer’s union with Christ: “Through faith in Christ, therefore, Christ’s righteousness becomes our righteousness and all that he has become ours; rather, he himself becomes ours.” Luther’s emphasis on “Christ becoming ours” is a much-needed corrective to those who simply see Jesus as a “Divine Genie” who gives them their “best life now.” I believe that the consumer mindset that is prevalent among Christians today is the result of a “me-centered gospel” that presents Jesus simply as a ticket to heaven, not a treasure to be adored. Christians must recognize that the joy of justification must not mainly center on the gifts they have received (legal transfer of riches) but on the Giver Himself. When union with Christ is reduced to the legal aspect, the believer misses the point of his justification. It is important to understand that God justifies the sinner by faith so he can have God as his greatest reward. Dr. Crouse rightly said that “The salvific benefits of Christ’s atoning work are enjoyed in the believer’s union with Christ.”
Another historical figure that emphasized the believer’s union with Christ was John Calvin. Marcus Johnson states:
Calvin followed Luther in asserting that faith was the means by which one comes into an intimate union with the salvific person of Christ. The believer possesses, or is engrafted into, Christ, and for this reason is graced with his benefits. This soteriological presupposition formed the basis for their shared understanding that justification is the direct consequence of this union; faith justifies by reason of the fact that faith joins one to the Christ who justifies.
Calvin states, “We must first understand that as long as Christ remains outside of us, and we are separated from him, all that he has suffered and done for the salvation of the human race remains useless and of no value to us. . . . All that he possesses is nothing to us until we grow into one body with him.” Hence, it is not surprising why Calvin calls “engrafting into Christ” as “the central doctrine.” From this perspective one can conclude that justification would be of no value if it does not unite the believer to Christ. Furthermore, like Luther, Calvin compared the believer’s union with Christ to the union of a man and woman in marriage: “A sacred wedlock through which we are made flesh of his flesh and bone of his bone (Eph. 5:30), and thus one with him.” By using the marriage imagery, Luther and Calvin were able to show that the believer’s union with Christ is not only forensic but also organic. Johnson notes, “The intimacy of the language Luther employed to characterize this faith union is striking. It is clear that Luther had more in mind here than a union of wills or a merely intellectual or legal union.” Hence, Christians must see the need to cultivate their intimacy with God daily through prayer, Scripture meditation, worship, fellowship, and reliance on the Holy Spirit. They need to recognize that their union with Christ not only changes their identity but it also establishes their intimacy with Him. In other words, being united to Christ is the highest good because God’s goal in redemption is not just forgiveness of sin but fellowship with God. The Apostle Paul understood this truth; he knew that his justification became the means by which he can know Christ more intimately. When Paul wrote his epistle to the church in Philippi, he had been a Christian for many years, and yet he was still eager to know Christ Jesus his Lord (Php 3:8). Furthermore, Paul knew that his union with Christ was the greatest gift he received in his salvation (Phi 3:8-14). Mark Garcia notes, “Ultimately for Paul, the gift of salvation (cf. Eph 2:8) is the gift of Christ himself, and he is our salvation inasmuch as we are united to him. The structural or conceptual note sounded here, then, is one that places beyond doubt that union with Christ, rather than any particular benefit of that union is, the substantia of salvation; it is what salvation actually is.” Indeed, Paul’s example should challenge the church to reclaim the importance of this truth. If believers understand the relationship between their justification and union with Christ, they will enjoy their relationship with Christ and the spiritual blessings they have in him (Eph 1:3). Moreover, understanding justification within the concept of union with Christ can help those who are struggling with condemnation and guilt. In light of the believer’s justification and union with Christ, Paul asserts, “Therefore, there is now no condemnation for those who are in Christ Jesus, because through Christ Jesus the law of the Spirit who gives life has set you free from the law of sin and death” (Rom 8:1-2 NIV). In the area of preaching, pastors who understand the implications of justification and union with Christ would not engage in moralism because they know only the gospel has the power to free the sinner from sin’s power and penalty. A sermon that is devoid of the gospel will only produce members who know many “how-tos” but cannot apply what they have learned in a way that leads to true transformation. On the contrary, spiritual renewal can be experienced by those who know that they have been justified by faith and united to Christ.
- Sanctification within the concept of union with Christ
When the Reformers championed the doctrine of justification by faith during the Reformation, the Roman Catholic church accused them of being antinomian. Both Luther and Calvin defended their position and argued that a right understanding of justification does not engender antinomianism but motivates believers to pursue holiness in their sanctification. Luther believed that the believer’s alien righteousness is the basis of his actual righteousness. Hence, in Luther’s view, believers who have been declared righteous by God are empowered to express their faith through love and good deeds. Johnson states:
Although Luther had not clearly conceptually distinguished between justification and sanctification in his theology—a distinction that evolved during his lifetime—his claim that faith justifies and transforms is important. Faith, because it is the possession of Christ, brings not only justification but also the power of the indwelling Christ. If Christ lives in the heart, the believer surely experiences the governance of Christ in her life.
Concerning Calvin’s understanding of the relationship between justification and sanctification within the concept of union with Christ, Johnson explains, “Even as Calvin clearly distinguished between justification and sanctification, his sentiment was nearly identical: the Christ possessed by faith is the effectual agent of reconciliation and renewal. It is this union with Christ on which the entirety of the Christian life depends.”
The Apostle Paul also saw how the believer’s union with Christ motivates him to live by faith. For example, in Galatians 2:20, Paul saw himself as being crucified with Christ. In his commentary on this verse, Calvin shows how Paul’s union with Christ gave him the power and the motivation to please God:
It is a remarkable sentiment, that believers live out of themselves, that is, they live in Christ; which can only be accomplished by holding a real and actual communication with him. Christ lives in us in two ways. The one life consists in governing us by his Spirit, and directing all our actions; the other, in making us partakers of his righteousness; so that, while we can do nothing of ourselves, we are accepted in the sight of God. The first relates to regeneration, the second to justification by free grace.
Garcia also noted how Calvin argued from 1 Corinthians 1:30 “to clarify the distinct-yet-inseparable character of the saving benefits (the duplex gratia) that come in union with Christ.” Garcia notes:
For example, in the first (1536) edition of his Institutes, Calvin’s affirmation of the necessity of Christian holiness is rooted in the implications of the Christ/ Spirit relationship for a proper understanding of union with Christ. If Christ the Mediator, who was and is filled with the Spirit of holiness, is made ours, we too share in the same Spirit. So, Calvin argues that to be a Christian under the law of grace does not entail moral license. Rather, by Christ’s righteousness we are made righteous and become fulfillers of the law. . . . Thus is fulfilled Paul’s statement: Christ was made righteousness, sanctification, and redemption for us.
While Calvin did not deny the security of the elect, he saw growth in holiness and perseverance as marks of authentic faith. In other words, his view of salvation was not limited to an event that took place in the past but something that continues to be a present reality in the life of the believer. Furthermore, in Romans 6:2, Paul asked a rhetorical question to point out that those who have died with Christ have died to sin. Hence, Paul never used God’s grace as a license to sin (Rom 6:1) but used it as a motivation to live for Christ. In light of his union with Christ, Paul resolved to live by faith in the Son of God, who loved him and gave himself up for him (Gal 2:20). Paul develops this idea in Romans 6:6-14. For Paul, those who have been united to Christ have crucified the old nature and are no longer slaves to sin (Rom 6:6;12) because they have been given new life in Christ (Rom 6:11) and are under grace (Rom 6:14). Moreover, they will not abuse the grace of God by sinning willfully because they know that their bodies are members of Christ himself (1 Cor 6:15).
Understanding sanctification within the concept of union with Christ can impact preaching and counseling in the following ways:
- When a preacher knows how the doctrine of union with Christ motivates believers to pursue holiness in their sanctification, he can protect the church from legalism and antinomianism. His members will not view obedience as a way to merit God’s love but will see it as a way to express their love for Him (Jn 14:15).
- Regarding counseling, the counselor can encourage the counselee by affirming the spiritual realities he has through his union with Christ. I think one of the reasons why some Christians go through depression is because they have forgotten the spiritual blessings they have in Christ. But when the counselee is reminded of his riches in Christ, he is able to face his trials with renewed strength because he knows that he is complete in Christ and there is nothing that could ever separate him from the love of God that is in Christ Jesus (Rom 8:38-39).
- Glorification within the concept of union with Christ
While the believer has not fully realized all the divine favors he has in Christ, Paul speaks of him as being seated with Christ in the heavenly places (Eph 2:6). From this perspective, Paul is so sure about the believer’s glorious future in Christ that he writes it as if it has already happened. Moreover, the golden chain passage in Romans 8:29-30 shows how God secures the salvation of the elect from start to finish. The Ligonier writing team notes:
Although this chain does not specifically mention everything that God does in redeeming us (we do not find the word sanctification in this passage), it does tell us that salvation is from start to finish a work of the Lord. It is not that God initiates our salvation and we complete it by our obedience. Our service to God is important and even a preparation for heaven, but it does not merit heaven or get us there finally. God and God alone saves. He starts the work and finishes it without any help from us.
It is interesting to note that in Romans 8:30, Paul talks about the Christian’s glorification in the past tense. Jesus has not returned yet but Paul is so sure about their glorification that he speaks of it as having occurred already. It can be argued that because Jesus experienced a bodily resurrection, those who are united to him will also experience a bodily resurrection when Christ returns. Horton notes, “Looking to our glorified Head, we are already assured of our future destiny; therefore, we do not fear death as an everlasting curse (Ps 23:4; Heb 2:15; Ro 8:38–39; 1 Co 15:55–57; Php 1:21–23; 2 Co 5:8).” John the Beloved also anticipated the time when the believer’s faith would be turned into sight when Christ returns: “Beloved, we are God’s children now, and what we will be has not yet appeared; but we know that when he appears we shall be like him, because we shall see him as he is” (1 Jn 3:2 ESV). John MacArthur provides a helpful commentary on this verse:
When Christ returns, he shall conform every believer to his image, i.e., his nature. A tension exists between the first part of the verse (“we are God’s children now”) and the latter part (“we shall be like him”). Such tension finds resolution in the solid hope that at Christ’s return the believer will experience ultimate conformity to his likeness (Rom 8:29; 1 Cor 15:42-49; Phil 3:21).
I also want to point out that the believer’s union with Christ assures him that he will be with Christ immediately after death. This is important to note because there are unbiblical perspectives on death: the exiled soul (the goal in this view is liberation from the body) and materialism (a person regains self-consciousness only after the resurrection of the body; “soul sleep”). These views are problematic because the Bible teaches that those who have died are aware that they are in the presence of the Lord (2 Co 5:8; Ps 16:10; 49:7-15; Ecc 12:7; Lk 16:22; 23:43; Php 1:23; 2 Co 5:8; Rev 6:9-11; 14:13). Hence, the reason why the Apostle Paul can say “to die is gain”(Php 1:21) is because he understood that “to be absent in the body is to be at home with the Lord” (2 Cor 5:8). While believers enjoy God’s presence in the intermediate state, they still await the resurrection of their bodies for their salvation to be fully realized. During this time, Horton notes, “The soul is preserved in blessedness until it is finally reunited with our flesh on the last day.” Understanding glorification within the concept of union with Christ can strengthen the believer’s faith especially during times of adversity. The reality of death has become more real to people because of the pandemic. Many are living in fear because they do not know what awaits them after death. But Christians do not have to live in despair because they know they are heaven-bound. Furthermore, as Christians look forward to their heavenly home, they need to remember that their longing for heaven must ultimately be a longing for Christ. Wayne Grudem provides a helpful reminder:
But more important than all the physical beauty of the heavenly city, more important than the fellowship we will enjoy eternally with all God’s people from all nations and all periods in history, more important than our freedom from pain and sorrow and physical suffering, and more important than our reigning over God’s kingdom—more important by far than any of these will be the fact that we will be in the presence of God and enjoying unhindered fellowship with him.
As I have examined the believer’s justification, sanctification, and glorification within the concept of union with Christ, I conclude that Christians miss a lot of theological insights and biblical principles when they do not understand how their union with Christ relates to their salvation. I have observed that most Christians view salvation in the past tense and do not see their salvation as a present and future reality. But when salvation is understood within the concept of union with Christ, believers are motivated to know Christ intimately and grow in Christlikeness. Moreover, the blessed hope they have in Christ (Tit 2:13) can serve as an anchor when they go through storms in life. Lastly, when union with Christ becomes the central doctrine in one’s life, Christ is enjoyed as the most valuable treasure (Phil 3:7-8)—imitated as the greatest example (Jn 13:15)—and relied on as the ultimate promise keeper (2 Cor 1:20; Jn 14:3).
Calvin, John. Commentaries on the Epistles of Paul to the Galatians and Ephesians. Translated by William Pringle. Edinburgh: The Calvin Translation Society, 1854.
Calvin, John. Institutes of the Christian Religion. Translated by Ford Lewis Battles. Louisville, KY: Westminster John Knox Press, 2006.
Garcia, Mark. “Imputation and the Christology of Union with Christ: Calvin, Osiander, and the Contemporary Quest for a Reformed Model,” Westminster Theological Journal 68 (2006): 219-251.
Grudem, Wayne. Systematic Theology. Grand Rapids, MI: Zondervan, 1994.
Horton, Michael. Pilgrim Theology. Grand Rapids, MI: Zondervan, 2011. Digital.
Johnson, Marcus. “Luther and Calvin on Union with Christ,” Fides et Historia 39, no. 2 (Summer/Fall 2007): 59-77.
Ligonier Ministries. “The Golden Chain of Salvation,” Last modified June 30, 2014. https://www.ligonier.org/learn/devotionals/golden-chain-salvation.
Luther, Martin. Luther’s Works, 55 vols., ed. Jaroslav Pelikan. St. Louis: Concordia Publishing House; Philadelphia: Fortress Press, 1955-1975.
Luther, Martin. Two Kinds of Righteousness. New York: Anchor Books, 1961.
MacArthur, John. The MacArthur Study Bible. Wheaton, IL: Crossway, 2010.
 Michael Horton, Pilgrim Theology (Grand Rapids, MI: Zondervan, 2011), 271, Digital.
 Martin Luther, Luther’s Works, 55 vols., ed. Jaroslav Pelikan (St. Louis: Concordia Publishing House; Philadelphia: Fortress Press, 1955-1975), 31:298.
 Robbie Crouse, Video Lecture. Knox Theological Seminary, Ft. Lauderdale FL, Lesson 23, March 22, 2021.
 Marcus Johnson, “Luther and Calvin on Union with Christ,” Fides et Historia 39, no. 2 (Summer/Fall 2007): 75.
 John Calvin, Institutes of the Christian Religion, ed. John T. McNeill, trans. Ford Lewis Battles (Louisville: Westminster John Knox Press, 2006), 3.1.1.
 Robbie Crouse, Video Lecture. Knox Theological Seminary, Ft. Lauderdale FL, Lesson 23, March 22, 2021.
 John Calvin, Institutes of the Christian Religion, ed. John T. McNeill, trans. Ford Lewis Battles (Louisville: Westminster John Knox Press, 2006), 3.1.3.
 Marcus Johnson, “Luther and Calvin on Union with Christ,” Fides et Historia 39, no. 2 (Summer/Fall 2007): 65.
 Mark Garcia, “Imputation and the Christology of Union with Christ: Calvin, Osiander, and the Contemporary Quest for a Reformed Model,” Westminster Theological Journal 68 (2006): 227-228.
 Martin Luther, Two Kinds of Righteousness, LW 31:293–298.
 Marcus Johnson, “Luther and Calvin on Union with Christ,” Fides et Historia 39, no. 2 (Summer/Fall 2007): 72.
 Ibid., 73.
 John Calvin, Commentary on Galatians, 2:20; CO 50: 199-200.
 Mark Garcia, “Imputation and the Christology of Union with Christ: Calvin, Osiander, and the Contemporary Quest for a Reformed Model,” Westminster Theological Journal 68 (2006): 231.
 Ibid., 231.
 Robbie Crouse, Video Lecture. Knox Theological Seminary, Ft. Lauderdale FL, Lesson 23, June 4, 2021. Lesson 55.
 “The Golden Chain of Salvation,” Ligonier Ministries, last modified June 30, 2014, https://www.ligonier.org/learn/devotionals/golden-chain-salvation.
 Michael Horton, Pilgrim Theology (Grand Rapids, MI: Zondervan, 2011), 422, Digital.
 John MacArthur, The MacArthur Study Bible (Wheaton, IL: Crossway, 2010), 1918.
 Michael Horton, Pilgrim Theology (Grand Rapids, MI: Zondervan, 2011), 424, Digital.
 Ibid., 424.
 Ibid., 425.
 Ibid., 423.
 Wayne Grudem, Systematic Theology (Grand Rapids, MI: Zondervan, 1994), 1164.