Living In Union With Christ: Paul’s Gospel and Christian Moral Identity: A Review

Living In Union With Christ: Paul’s Gospel and Christian Moral Identity by Grant Macaskill

Baker Academic, 2019, $24.99, pp. 179

Though confusion afflicts the Church in every age, ours is one especially prone to misunderstand the basic nature and purpose of the Christian life. When forced to answer questions about personal identity and self-understanding, many within the Church rely far more on individualistic self-determination than anything distinctively Christian. Then, when suffering accosts us unexpectedly, our sense of self is shattered. Our sense of identity consists in the things we know or the things we do. This might impress others temporarily, but it crumbles when we next err, receive heartbreaking news, or experience real evil or malice. But the Christian life is not only (or not even primarily) about us, our happenings, and our doings.

Grant Macaskill’s 2019 book, Living in Union with Christ, contributes powerful resources for understanding how and why union with Christ informs the whole of the Christian life. Macaskill, the Kirby Laing Chair of New Testament Exegesis at the University of Aberdeen, has tackled the subject previously in his 2013 book Union with Christ in the New Testament, tracing the doctrine’s reception history from the Church Fathers to the magisterial Reformers and modern theologians, before offering a careful exegetical account of the New Testament data. Living in Union with Christ is based on lectures delivered at Reformed Theological Seminary, but it is not merely a condensed popularization of his prior book. New material particularly focuses on the contribution of the Pauline epistles to our understanding of how union with Christ informs Christian identity and moral agency. Macaskill’s prose is inviting, and reminds the reader throughout why all of this matters. The book’s tone is not light, but nor is it dense or inaccessible to non-scholars. For instance, Macaskill throughout introduces his interlocutors with brief descriptions of their views, particularly on matters familiar to Pauline specialists but less well-known to non-specialists and lay readers.

Macaskill states that “the core claim of this book is that all talk of the Christian moral life must begin and end with Paul’s statement ‘it is no longer I who live, but Christ who lives in me’ (Gal. 2:20), and must understand the work of the Holy Spirit rightly in relation to Christ’s presence. This assertion is the sine qua non of the Christian moral life, which is rendered void in its absence” (1). Macaskill’s own summary of his basic claim and its significance is worth quoting at length:

“The key point explored in some detail through the body of this book can here be summarized in terms of the prepositions that govern it. Jesus Christ is not represented simply as the one through whom we have forgiveness, or even as the one by whom the moral life is exemplified, but as the one in whom the life of discipleship takes place. Christ himself is present in the life of the disciple as the principal moral agent. We are not simply saved by him, nor do we merely follow after him – though both of these continue to be true – but we participate in him. This is why Paul so frequently specifies that the realities of the Christian life are “in Christ.” …The Spirit, meanwhile, who is so important to Paul’s account of the moral life, is represented not as helping us to fulfill our frustrated potential but as realizing with us the identity of the Son, and he does this because he himself is the Spirit of the Son (Gal. 4:6).”


According to Macaskill, for Paul, Christ himself is the acting subject of the Christian life as the Spirit of God manifests Christ’s presence in us (66). The Christian life is not merely something we undertake as discrete individuals, acting in various degrees of success and failure on the basis of our own potentialities. Yet, neither is it the case that in Christ we cease to exist as our particular selves, as if only Christ himself is ever the acting subject amidst our ongoing failures. Rather, we who have been crucified with Christ no longer live, but Christ lives within us, as we live by faith in the Son of God who loved us and gave himself for us.

Macaskill explicitly builds upon Calvin’s reading of union with Christ in Paul, in which the “double grace” of justification and sanctification are apprehended distinctly but inseparably as the Holy Spirit unites us with Christ by faith. Macaskill develops a reading of Paul that accounts for what traditional Protestant dogmatics referred to as the “alien righteousness” of Christ, but in a way that challenges how modern people tend to conceive of the self as discrete and buffered from external influences. Drawing on the work of Susan Eastman, Macaskill describes how, for Paul, the self can be indwelt by the controlling power of sin (Rom 7:20), or the risen Christ (Gal. 2:20).

“Grant Macaskill’s 2019 book, Living in Union with Christ, contributes powerful resources for understanding how and why union with Christ informs the whole of the Christian life.”

Macaskill first sketches recent attempts to revise our understanding of justification and sanctification in Paul, narrating roughly the last fifty years of New Testament scholarship. He expresses both appreciation and criticism towards the readings of Paul from the 1970s and 1980s which laudably sought to correct prejudices and caricatures about his Second Temple Jewish context, but involved less sustainable accounts of Paul’s Christology (e.g. Dunn and Wright) (20).

Finally, Macaskill is concerned that the popular practice of contemporary churches, sometimes in unintended but nonetheless real contradiction of their own theological traditions, displays an inadequate grasp of union with Christ in Christian moral agency, in a variety of mutually exclusive ways (3). For example, routinely, in popular piety, Christ is reduced to a moral exemplar for imitation; or, conversely a right emphasis on the incongruity of God’s grace becomes a license to sin. Elsewhere churches and their members might clearly understand that Christ died and rose for our justification, but then conclude that he gave us the Holy Spirit so that, from here on out, we can grow in obedience apart from our union with Him.

Macaskill offers a better path forward, arguing that a properly Christian account of moral agency will hold that Christ himself lives and acts within the self as it is reconstituted in union with Christ. Put another way, although the revival of virtue theory in the past few decades in theology and Protestant ethics has been salutary in many respects, its explanatory power for moral agency in Paul is limited, because the existence we have in Christ shatters the mold of the gradually improving self (25).

“Christ himself is the acting subject of the Christian life as the Spirit of God manifests Christ’s presence in us.”

Chapter two especially focuses on Paul’s claim in Galatians 2:20; chapter three clarifies how Paul uses baptismal and clothing language to locate Christian existence within Christ himself; chapter four explores Paul’s Christological re-working of covenantal and exodus traditions from Israel’s scriptures, especially the Shema of Deuteronomy 6:4. A powerful and unique contribution in this regard are Macaskill’s arguments for the priority of divine unicity and divine simplicity as informing Paul’s Christological and participatory reading of scripture. Chapter five outlines how the Holy Spirit is crucial to Christian moral agency and Christ’s indwelling of his members, particularly focusing on Paul’s arguments in Galatians 3–4 that the Holy Spirit is the Spirit of the Son, received through our adoption.

Chapter six is perhaps the most pastorally rich, clarifying how Christian hope is determined by our union with Christ as the Spirit realizes Christ’s life and victory in us, even as we suffer and struggle. Macaskill writes:

“By linking Jesus’s past and future to Christian moral identity and understanding that identity as constituted by the acting presence of Christ in our lives now, we see it in terms very different from the ones in which it is often cast. We do not only look back at a past event from which we benefit, a transaction made on our behalf, and we do not only look forward to a future in which we will be definitely better. We look back to a past that is ours now, and as with all backstories, it defines who we are. At the same time, we look forward to a future that will bring to its perfect realization what we genuinely are, as we are in Christ.”


Each small act of obedience is the Spirit’s work manifesting Christ’s presence in our lives and our world. But particularly amidst suffering, bewilderment, and lack of assurance, “we have the Spirit of the Son in us, and when our own spirits have nothing to give and no hope in themselves, his Spirit lifts us up and helps us to trust and testify that we are children of God” (123). A final, brief chapter offers a panorama of the new horizons that unfold upon rightly apprehending life in union with Christ. Our sense of our own selves, our outlook on how people change, our obligations of love amidst contemporary divisiveness in the bonds of unity established by Christ himself, what exactly the problem with legalism really is, our notions of virtue, and how the doctrine of the Trinity relates to the Christian life are all refracted through our union with Christ.

“Macaskill offers a better path forward, arguing that a properly Christian account of moral agency will hold that Christ himself lives and acts within the self as it is reconstituted in union with Christ.”

Overall, Macaskill has contributed a theologically informed and exegetically sustainable account of moral agency in Paul’s epistles, filled with rich pastoral implications. A matter of clarity that might improve the argument of this book concerns the place of Galatians 2:20 as the key to the whole of Christian moral agency. In his prior book Macaskill helpfully established how participatory motifs are used throughout the entire New Testament. But, as stated, Macaskill writes that “all talk of the Christian moral life must begin and end with Paul’s statement ‘it is no longer I who live, but Christ who lives in me’ (Galatians 2:20)” (1). If by this Macaskill only wishes to indicate that Galatians 2:20 is a crucial and often neglected passage for reflecting on Christian moral agency, then this is true enough. But necessary, too, is further development of the canonical and dogmatic principles outlining how Paul’s declaration relates to non-Pauline passages of Scripture that bear on theological ethics.

I want to suggest four reasons why I hope Grant Macaskill’s Living in Union with Christ receives a wide hearing. First, this book represents a masterful example of historically-informed theological interpretation rendered in engaging prose. It is unsurprising when critical historians are indifferent or outright hostile towards Christian theological interpretation, but it is always disappointing when Christian scholars working in biblical studies are unaware of why historic doctrines such as divine simplicity matter. Macaskill charts a rare course, drawing not only upon his expertise in apocalyptic and early Jewish literature but further showing how classical trinitarianism and conciliar Christology are crucial for reading the New Testament today.

Second, there are significant ethical and even political implications to an account of Christian moral agency informed by union with Christ. At a bare minimum, our pervasively individualistic tendencies in the modern West must be challenged by realizing that we have put on Christ in baptism, and we belong not only to ourselves but to God and others. To that end, Macaskill’s book is a welcome aid.

Third, Macaskill contributes a resourceful account of Christian hope. It can be difficult to sense that Christ is truly living within us in the suffering and drudgeries of daily life, let alone in the seemingly constant moral failure we encounter, both in the Church and in ourselves. Macaskill’s account of the Holy Spirit manifesting Christ’s presence in our lives in even the smallest victories shines light into the darkness experienced by those who desire to change but despair at what can feel like constant or inevitable failure.

Finally, any serious reckoning with Christ himself will be a word that cuts us and heals us. Are our churches– are we–known for the Spirit of God realizing Christ’s presence in us through love for God and neighbor? Routinely, while reading and re-reading Macaskill’s Pauline exegesis, I had to put the book down and reflect on the default understanding of moral agency not only “out there” among others but also in myself. I was forced to examine the notions of moral agency with which I consistently operate. It is tempting to imagine myself as an autonomous unit, in control of my life, safe from moral contagion, master of my own destiny before God and others–but this is all a lie. Our only comfort in life and in death is in our belonging to and participation in Christ. We need this fresh reminder that the hope of glory, “Christ in you,” is put in weak and fragile vessels to show that the all-surpassing power of the gospel belongs to God and not to us (Col 1:27, 2 Cor 4:7). Even those who already believe union with Christ is important–perhaps especially such persons–tend on a daily basis to regard ourselves as the primary acting subjects of our moral lives. We need to be slain and enlivened afresh by the Word of God, again and again, whose apostle teaches us, “it is no longer I who live, but Christ who lives in me.”

Joshua Heavin is an adjunct professor in the school of Christian Thought at Houston Baptist University. He received his MDiv at Redeemer Seminary, wrote his doctoral dissertation at the University of Aberdeen (Trinity College Bristol), and currently lives with his family in Dallas, Texas.


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