Reviewed by David Knierim
Over the last several years, the doctrine of union with Christ has experienced renewed interest in Evangelical scholarship. Several contemporary treatments on union with Christ have been published such as Paul and Union with Christ: An Exegetical and Theological Study by Constantine R. Campbell (2012), One with Christ: An Evangelical Theology of Salvation by Marcus Peter Johnson (2013), and Union with Christ in the New Testament by Grant Macaskill (2014). Robert A. Peterson’s book Salvation Applied by the Spirit: Union with Christ complements contemporary literature by providing a comprehensive overview of union with Christ in both Scripture and theology.
Salvation Applied by the Spirit is the second book in a planned three-part series. The first book, Salvation Accomplished by the Son: The Work of Christ, was released in 2011; it provides an in-depth treatment of the redemptive acts of Christ. The planned third work Salvation Planned by the Father: Election in Christ will deal with the doctrine of election. The book’s author, Robert A. Peterson, is a professor of systematic theology at Covenant Theological Seminary and has authored numerous books and articles as well as co-edited several works.
Union with Christ in Scripture
Peterson divides his treatment of union with Christ into two sections: union with Christ in Scripture and union with Christ in theology. He begins the first section (union with Christ in Scripture) in chapters 1-3 by discussing portions of Scripture that lay the foundation for union with Christ in the New Testament. Chapter 1 focuses on union with Christ in the Old Testament. Using categories drawn from Campbell’s work Paul and Union with Christ, Peterson discusses how union with Christ is foreshadowed in the Old Testament via three main concepts:  identification,  incorporation, and  participation. He then exegetes several key Old Testament passages for each of these three categories. He follows a similar pattern in chapters 2-3, once again using Campbell’s three concepts of identification, incorporation, and participation as well as exegesis to show how the synoptic gospels and Acts foreshadow union with Christ in the New Testament.
Peterson continues his exposition by discussing union with Christ in the Gospel of John (ch. 4). He invests the majority of his time in chapter 4 detailing the mutual indwelling of the Trinity in believers, which he infers from both the co-inherence of the Father and the Son and the Son’s indwelling of believers (68).
Next, Peterson considers union with Christ in the Pauline epistles. His treatment of union with Christ in Paul composes the bulk of his treatment of union with Christ in Scripture; altogether, he spends ten chapters exegeting the Pauline epistles (chs. 5-14) and two summarizing his findings (chs. 15-16). Through his exegesis, he identifies two categories of “in Christ” language in Paul: broad and narrow. Broad usages of “in Christ” do not primarily address union with Christ, but still convey a personal relationship between Christ and the believer; specifically, they indicate  agency (something God accomplishes through Christ),  association (relationship between Christ and believers),  cause (something done because of Christ’s person and work),  instrument (something done by means of Christ),  manner (the way something should be done),  object of faith (portrays Christ as the personal object of faith),  periphrasis for “Christian” (equivalent to the adjective “Christian”),  or realm, sphere, or domain (the area over which Christ has dominion) (186-88). Narrow usages refer directly to union with Christ (186-88). Peterson argues for nine total texts that convey union with Christ in a narrow sense:  1 Corinthians 1:30-31,  2 Corinthians 5:21,  2 Corinthians 13:3-6,  Ephesians 1:7-10,  Ephesians 6:10-12,  Philippians 3:8-11,  Colossians 2:9-10,  1 Thessalonians 1:1, and  2 Thessalonians 1:1-2 (188-92).
Peterson also ascertains from his exegesis in Paul that believers participate in certain aspects of Jesus’ narrative: “Specifically, they [believers] die with him, are buried with him, are raised with him, ascend with him, sit down with him in heaven, and amazingly, in a sense, will even come again with him” (197). Furthermore, Peterson contends that the presence of union with Christ in Paul’s greetings indicates the importance of union with Christ in his thought (185) and that Paul’s language of believers being “in” the Father and Son designates that believers are joined to the Father, Son, and Spirit by union with Christ (195-97). He concludes his treatment of union with Christ in the Pauline epistles in chapter 16 by detailing six pictures and themes in Paul that present union with Christ, namely, body of Christ, temple, marriage, new clothing, filled to all fullness, and indwelling.
Chapters 17-20 complete Peterson’s exposition of union with Christ in Scripture by expositing passages from Hebrews (ch. 17), 1-2 Peter (ch. 18), and 1 John (ch. 19). His treatment of 1 John in chapter 19 builds on his treatment of John’s Gospel by indicating that the reciprocal indwelling of God in believers has ethical connotations; believers are to obey God’s commands, confess Jesus is God’s Son, and continue in love on account of God’s indwelling presence in their lives. He concludes by exegeting passages that deal with union with Christ in Revelation (ch. 20).
Union with Christ in Theology
Peterson opens his section of union with Christ in theology by delineating how union with Christ fits in with the biblical storyline: eternity past, creation, the fall, the incarnation, Christ’s work, and new creation (ch. 21). A few highlights from this chapter are his discussion of the connection between union with Christ and creation as well as union with Christ in eschatology. With regard to creation, Peterson accents the importance of man being made in the image of God for union with Christ; being made in the “image of God” is a prerequisite for union with Christ as it ensures humanity’s ontological compatibility for union with Christ (279-81). Peterson also emphasizes the eschatological dimension of union with Christ. He asserts that all creation will be united to Christ in the sense that Christ will restore harmony in the universe and that believers will share in all of Christ’s redemptive events, which includes His second coming (291-94).
Peterson continues by discussing the Spirit’s role in union with Christ. In order to lay the foundation for this discussion, he presents a general exposition of the Holy Spirit’s personality, deity, and works (chs. 21-22); these chapters reflect content that is fairly standard in any orthodox, evangelical treatment of pneumatology. After this general exposition, he details the work of the Spirit in union with Christ (ch. 24). Specifically, he affirms that the Spirit is the bond of union with Christ or as Peterson eloquently writes “the necessary nexus between Christ and the believer” (320-22) and absolutely necessary in the salvation process (322-24). He finishes by detailing the Spirit’s role in salvation (= regeneration, justification, adoption, sanctification, preservation, glorification) and how each topic relates to union with Christ (324-47).
Next, Peterson explores the relationship of union with Christ to the person and work of Christ (ch. 25). Once again, his discussion is fairly standard; he covers such topics as Christ’s deity, incarnation, and resurrection. Peterson’s theological section continues by exploring union with Christ in the church (ch. 26) and the sacraments (ch. 27). Much of his discussion on union with Christ and the church repeats what was covered in his summary chapters on Paul (i.e. the church as a living temple, the church as the bride of Christ, etc…). His discussion of Christ and the sacraments argues that baptism signifies union with Christ while the Lord’s Supper is both a means of grace through which the gospel is proclaimed and a symbol of ongoing union with Christ (405-8). He concludes his treatment of union with Christ in chapter 27. He begins chapter 27 by defining union with Christ in a broad sense as encompassing the totality of salvation: election, Christ’s redemptive work on the cross, the application of salvation, and the final salvation of the church and created order (411). Additionally, Peterson makes the case for a more narrow sense of union with Christ as the application of salvation; this aspect of union with Christ, called faith union, occurs after faith is placed in Christ for salvation (412). He closes by explaining the implications of different aspects of the doctrine of union with Christ such as  the mutual indwelling of the Trinity in believers, which he argues should elicit praise, devotion to God, and involvement in God’s world mission in believers (417) and  the participation of believers in Jesus’ story (i.e. his suffering and future glory), which should encourage believers to persevere in the midst of trials due to the promise of future glorification (422-28).
There is much to be commended in Salvation Applied by the Spirit. One of the most striking elements of Peterson’s work is his exemplary theological method. Peterson commences his work by asserting the preeminence of Scripture in the development of doctrine by elaborating on the structure of his book: “There is a definite order. The Bible’s treatment of union must precede an attempt to understand its teachings” (14). This commitment to Scripture as the foundation for theology is evident throughout the book. From his exegetical summaries to his theological treatments, Peterson aptly demonstrates how the conclusions he reaches are based on Scripture. When he does contend for positions that are not directly stated in Scripture (such as the mutual indwelling of the Trinity in believers), he explains to the reader how his position is inferred from Scripture. His theological method is a notable feature of his book and is worthy of emulation by theologians, pastors, and students alike.
Peterson’s exegesis (like his theological method) is also superb. His handling of New Testament passages demonstrates a sound, orthodox hermeneutic. Even though he doesn’t specify all of the details about every text, it is evident that he has looked at these details and has a thorough understanding of each passage he exegetes. For the most part, Peterson keeps his exegesis at a very high level; however, he does expound details in the text and defend his position on exegetical details such as grammatical nuances (e.g. different interpretive options for the dative “in Christ”) when needed. He provides an excellent example of a theologian employing sound historical, grammatical exegesis as the foundation for his theological investigation.
Comprehensive Treatment of Union with Christ
Another outstanding feature of Peterson’s work is its comprehensive treatment of union with Christ. His treatment of New Testament passages that deal with union with Christ is exhaustive; his theological treatment is no less comprehensive in its scope. Many recent treatments of union with Christ focus on one particular area of study in union with Christ (e.g. Campbell’s Paul and Union with Christ that focuses on union with Christ in Pauline literature or Johnson’s One with Christ that focuses on union with Christ from a more theological perspective). Peterson’s work puts both a broad exegetical and theological treatment together in one book, which is its major contribution to recent literature on the subject.
At a high level, Peterson’s book is well-organized as he does an excellent job arranging his book around his exegetical and theological sections; however, the overarching themes and points in individual chapters can be difficult to follow. Many of his exegetical chapters – especially those dealing with the Pauline epistles – are composed solely of Peterson listing one passage after another along with his comments on each passage. Since many of these exegetical chapters do not contain any introduction or conclusion, it can make the major themes and points that he is developing elusive until they are laid out in his summary sections. His theological chapters are easier to follow as the points he is making are more clearly laid out; however, his theological chapters can be somewhat repetitive as many of the verses and themes that are covered in his exegetical chapters are repeated or summarized in his theological chapters.
Engagement with Scholarly Literature
Peterson does an excellent job consulting with relevant scholarly literature in his exegetical sections. He interacts with top scholars on every book that he exegetes and uses them to support and further elucidate his points. He also takes into account recent literature on union with Christ in his exegetical sections. For example, in his Pauline exegesis, he relies heavily on Campbell’s recent work Paul and Union with Christ. However, Peterson not only relies on Campbell, but also adds to what Campbell argues as he detects two verses that Campbell has now admitted he missed (1 Thessalonians 1:1 and 2 Thessalonians 1:1-2). These passages allude to the indwelling of believers by both the Father and the Son (167-68, 192, 195-97).
Peterson’s theological sections are not as comprehensive in their engagement with scholarly sources as his exegetical sections. Although Peterson does engage with some important works such as Union with Christ in Scripture, History, and Theology by Robert Letham or Redemption Accomplished and Applied by John Murray, his engagement with these works is often very brief. His interaction with major theologians who have a rich doctrine of union with Christ such as John Calvin is also notably sparse. His work would have benefitted from a more thorough engagement of the academic field of theology as well as some more analysis and critique of union with Christ in significant theologians such as John Murray or Michael Horton.
Overall, Peterson’s book delivers an excellent treatment of union with Christ. His exceptional theological method and exegesis provide a comprehensive overview of the doctrine from an orthodox, Reformed perspective. Pastors, students, and theologians who are looking for a broad summary of union with Christ in Scripture and theology should consider this book.
David Knierim is a graduate (PhD) of The Southern Baptist Theological Seminary.
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Salvation Applied By The Spirit: Union With Christ