Union with Christ and the Life of Faith

Fred Sanders. Union with Christ and the Life of Faith. Baker Academic, 2025. $22.99. 176 pp.

Three unions lie at the heart of the Christian faith: the union in the Holy Trinity of the three persons who are one God; the two natures, truly human and truly divine, that are united in the one person of Jesus Christ, our Lord and Savior; the union of Christ and his church that the Holy Spirit effects through faith. 

These unions lie at the very heart of our faith, yet they are deeply mysterious. God has revealed them to us by his Word, yet they are full of inexhaustible and infinite meaning that we strain to comprehend. We need a learned and devoted guide to explain these mysteries and their significance for the Christian life as a whole. 

For those searching for such guides, Fred Sanders’s short and accessible new book is a must-read not only for scholars but especially for preachers, teachers, and catechists (with the caveat that some vocabulary is above the lay level). What follows is an overview of the strongest contributions made in the book’s five chapters, followed by three questions for further reflection. 

The opening chapter advances the most provocative yet intuitive claim in this book—that “the historic Christian creeds (Apostles’ and Nicene) teach that salvation consists in union with Christ.” In short, the creed’s second article on what we believe about Christ eloquently states how redemption was accomplished, before the third article on the Holy Spirit expresses how that redemption is applied to us. This is very easy to miss altogether. Sanders explains:

The classical creedal-patristic articulation of union with Christ was so wrapped up in tracing the identity of Jesus and narrating his work that the conventional wisdom of our age sometimes fails to recognize it as soteriology at all. It was so baked into the creedal matrix that we are in danger of thinking they were talking about not union with Christ but just Christ himself. We can learn from something here: a doctrine of union with Christ should rivet our attention on Jesus Christ… the structure of Christian faith is itself a form of union with Christ; its first movement is rapt attention to Christ himself and its second movement is inclusion in him.

A key benefit of having a creedally-rooted soteriology is that it will not only be scriptural but will also illumine a common testimony that all Christians share in the divided body of Christ. This is not wishy-washy or lowest-common-denominator ecumenism, but a robust theological vision of what all Christians have always believed—namely, that union with Christ is at the heart of our common faith, expressed in the Apostles’ and Nicene creeds we confess together.

Subsequently, in chapter 2, Sanders argues that a theology of union with Christ informs the very structure of the New Testament canon. Modern historicist scholarship has spilt oceans of ink trying to identify the genre of the gospels, or why this particular genre (whatever it is) was used by early Christians to create what Justin Martyr called “memoirs” of Jesus. Still others have puzzled over why a collection of occasional letters to specific churches became religious texts. However, Sanders argues that a theological vision of union with Christ is the clue as to why we have both ‘gospels’ and ‘epistles’ in our New Testament canon. Exploring union with Christ is not merely a matter of paraphrasing Paul’s many “in Christ” phrases, though they are certainly important. Sanders explains:

Gospels… are not inert genres; they do not sit still and wait for application. They are instead the primal and inescapable literary form of the self-presentation of the risen Christ. They are in themselves already documents of union with Christ, and the implied reader is a disciple united to Christ’s life by faith… One benefit of gaining insight into the spiritual structure of inclusion in Christ is that it changes our posture toward the overall message of Scripture. Even while we continue to read the Bible to find its witness about union with Christ, we become aware that the Bible itself exists, in the very literary forms and genres in which it exists, because it is itself situated in Christ. Union with Christ is what summoned these particular genres of prophecy and promise, Gospel, and epistle.

Of course, the gospels are not merely narrations of how salvation was accomplished, since they contain exhortations. And the epistles are not bare statements of salvation’s application, since they presuppose some narrative of God’s saving action in Jesus Christ. Even so, a theology of union with Christ as the key to salvation’s objective accomplishment and subjective application, holds great explanatory power for considering why our New Testament canon took shape as it did.

The third chapter shows how a range of Christian traditions has explored the union with Christ, not always in the same idioms or emphases, but nonetheless with a common trinitarian and Christological core. Sanders is a perceptive reader of Calvin in particular, who famously declared that all Christ suffered and accomplished would be of no use if Christ remained outside of us, and we outside of him. 

Sanders provides a sobering, cautionary tale of how a theologian can have a strong central vision of union with Christ but evacuate it of its theological backbone. His case study, William Sherlock, developed an elaborate account of union with Christ, but without beliefs about a mysterious joining of believers with Christ. Rather, Sherlock interpreted this language to refer to belief in Christ’s teachings, obedience, and participation in the life of the church. As Sherlock writes, “it is not very intelligible how we can be or abide in the Person of Christ; and it is more unintelligible still, how we can be in the Person of Christ, and the Person of Christ at the same time be in us, which is a new Piece of Philosophy called Penetration of divisions.” Edward Polhill offered an astonishingly lengthy and insightful response to Sherlock, arguing that real, spiritual union with the person of Christ was the foundation on which all other goods cohere. 

With those creedal, scriptural, and historical contexts in place, the fourth chapter of this book develops a dogmatic soteriology of union with Christ. This chapter deserves closer attention in light of three contributions it makes.

First, Sanders enters into conversation with the Reformed tradition on the question of whether or not having a robust doctrine of union with Christ is compatible with having an ordo salutis (order of salvation). Sanders argues that union with Christ “is bigger, stronger, more organic, more primal, and more inclined to rivet our attention on Jesus Christ himself than is the ordo salutis tradition, but a well-explained order of salvation, even presented in chart format, can certainly play a valuable supporting role.” 

Second, Sanders boldly argues we need to cease and desist from speaking about “atonement theories” and instead contemplate a robust vision of our union with Christ as the key to not only redemption’s application but also its accomplishment. Though not explicitly conversing with him, Sanders makes a very similar argument to that of Khaled Anatolios in his Deification Through the Cross. Sanders argues: “modern discussions of the atonement have long been in notable disarray—and it is a kind of disarray that is antithetical to the unified treatment of union with Christ we are pursuing. There is fragmentation in modern atonement theology that needs to be repaired before we can begin to understand union with Christ as embracively including both the accomplishment and application of redemption.” 

Sanders here draws heavily upon Adam Johnson’s research on the history of atonement theology, which notes that the modern predilection for identifying various theories as a competing system has its roots in F.C. Baur’s Hegelianism, but was hitherto unknown in the history of Christian theology. Hegel’s “theories of atonement” model is so profoundly influential that many of us are unaware of its sources and can hardly think about the atonement apart from it. Yet Sanders cheekily notes that this approach:

…has a tendency to make students feel immediately wiser than all previous theologians (who were evidently never so flexible in their way of thinking about the subject and never even knew that they were operating with theories). As a settled set of presuppositions, or as the new orthodoxy about atonement, it is historically misleading, and it systematically hobbles in advance the possibility of thinking large, integrative thoughts about soteriology. 

Instead, the path forward, following Johnson and John Webster, “is not theories but Theoria, the Greek word for contemplation.”

Third, it is a false dichotomy to be anxious whether our theology should be Christocentric or trinitarian in its focus, because Christology and the Trinity are concentrically related in the architecture of a Christian theology of salvation. The problem or tension that not only academic theologians but also lay Christians might feel is framed as follows: 

There is a perceived difficulty in maintaining a concrete, definite focus on Jesus Christ as the center of salvation while also undistractedly recognizing the presence of God the Father and God the Holy Spirit in the same work. There is a felt tension, in other words, between soteriology’s Christocentric impulse, on the one hand, and its trinitarian impulse, on the other. This tension continues to be felt even among evangelical theologians who know there can be no real contradiction between the two. It is a tension that registers troublingly in the spirituality of ordinary believers.

On one hand, it is utterly obvious, correct, and healthy to focus on Christ because “our grasp of salvation is surest when it is most centered on Christ, when we look to him for ‘our whole salvation and all its parts,’” quoting Calvin. Yet, danger can also lie down this path, because while “the doctrine of union with Christ certainly seems to be a Christocentric soteriology, … yet it thrives and flourishes in an elaborately trinitarian setting.” After all, modalists and Arians and Socinians in their own heretical ways highly value union with Christ. Consequently, “when people ask whether our thinking should be Christ-centered or Trinity-centered, the obvious reply is to reject the false dichotomy being offered… if Christ and the Trinity are separate centers, they can only be related elliptically, or eccentrically. But they are instead concentric.” In sum:

We start our doctrine of union with Christ conceptually by placing Christ at the center of it and then inquiring about Christ’s own center. When we realize that his center is the Father, we recognize that in terms of good doctrinal order, we must in fact approach soteriology from the doctrine of God. The Father sends the Son to save in salvation history because the Father eternally begot the Son. It is because of the Son’s eternal generation within the Godhead that he is the one sent forth to save… Gregory of Nyssa puts it this way: ‘every operation… has its origin from the Father, and proceeds through the Son, and is perfected in the Holy Spirit.’ The one God does all things in this unified from-through-in way.

So, in terms of practical piety, Christians should be a profoundly Christ-centered people, but in so doing we will perceive the communion of the Father, Son, and Spirit as Christ’s own center. In terms of dogmatic idiom, our theology should begin with the eternal processions of the Son’s eternal generation and the Spirit’s spiration. We can then proceed to contemplate the missions of the Son and Spirit. In the undivided, outward works of the one God towards creation, the Father, Son, and Holy Spirit work inseparably to bring creatures into saving union with Christ.

Finally, in chapter five, Sanders notes that although there is tremendous variety in the actual lives lived by those who are united with Christ, union with Christ nonetheless gives a consistent form to the Christian life: “a descent and ascent, a dying and rising to true life,” which is quintessentially signified in Baptism and the Lord’s Supper. Sanders notes how theologians such as Zanchi, Horatio Bonar, and Walter Marshall in The Gospel Mystery of Sanctification all thought it was possible to distinguish between multiple kinds of unions we have with Christ, quintessentially in Christ’s union with humanity by his incarnation, and our union with him already in this age, and one in glory that is not yet fully realized.

Overall, as is characteristic of everything Fred Sanders writes, this book is a joy to read. Sanders is far more than an insightful critic or skilled teacher; his infectious delight in the subject matter shines through. Upon setting this book down I wanted my attention to be ever more riveted upon Jesus Christ, certainly when thinking dogmatically about soteriology, but especially so in my day-to-day life and trials.

Second, a great delight of this book was discovering a host of interlocutors on union with Christ who are too little known. The exchange between Sherlock and Polhill centuries ago has been recycled (unawares, as best I can tell) in the last fifty years of debates in Pauline scholarship on “participation in Christ/union with Christ.” Some of these forgotten conversations of the past can and should reframe those contemporary conversations. If there is only one further person I wish Sanders had included, I was surprised that N. Herman Ridderbos did not factor into this book. Including him could have helped Sanders’s case on two points. First, Ridderbos coined the phrase historia salutis to complement ordo salutis and frame union with Christ as the link between the two. And second, Ridderbos’ Redemptive History and the New Testament Scriptures does not make precisely the same argument about the canon Sanders makes, but nonetheless very similar.

Third, a strength of this book is its brevity. Those who want to probe further into this topic might regard it as a prelude to further reading elsewhere. Given that the topic is massive, I was left wondering how Sanders’ approach to union with Christ related to numerous debates in the history of Christian theology over how best to understand union with Christ, from intra-Lutheran controversies over participation involving Osiander, to numerous intra-reformed debates over the precise nuances of union with Christ, to post-Palamite approaches to theosis and an “essence/energies” distinction in the East, to post-Tridentine Roman Catholic approaches to union/participation. 

For a practical or pastoral example, I have often found that speaking about our “union with Christ” or “participation in Christ” in popular parlance is heard by not a few people as a reference to our ongoing relationship with Jesus Christ. This is certainly important. However, as Sanders is well aware, the objective accomplishment of our salvation in Christ is something the Holy Spirit subjectively applies in the concrete, particular details of our ongoing relating to Christ through the means of grace. 

It can be challenging when preaching or teaching at the popular level to clearly and consistently communicate that vision. Much work remains, but those who attempt to undertake it can do so by building upon the joyful trajectory sketched by Fred Sanders, riveting our attention on Jesus Christ.