I recently read The Christian Life: A Doctrinal Introduction by Sinclair B. Ferguson as it came into my possession, and I wanted to compare his position on union with Christ with that of James D. Gifford Jr. and others I have been studying. As I worked through his chapter, I found myself wrestling with a tension. Ferguson’s view, at least as presented here, feels more like a kind of membership than a truly vibrant relationship. And yet, from experience, I know the relationship is more than what he describes.

This is another entry in my ongoing series exploring what it means to be in Christ and for Christ to be in us. There are many ways to describe this reality, but for now I am using the language of a “third type of perichoretic relationship” or “perichoretic salvation.” If you have been following along in this series, you will know this is part of a larger conversation that is still unfolding.

Ferguson devotes one chapter of his book to union with Christ. It spans less than nine and a half pages out of 188. That alone is striking given how central the topic is. In his opening, he rightly emphasizes its importance, writing, “The truth to which the New Testament constantly returns is that as Christians we are united to Christ.” And in his conclusion he reinforces this, stating, “Of all the doctrines surrounding the Christian life this, one of the profoundest, is also one of the most practical in its effects.” He is absolutely right on both counts. Which only raises the question, if this is so central and so profound, should there not be more here?

Ferguson defines being “in Christ” as being people set apart by and for God (page 97). He goes on to say, “These expressions indicate the closeness of the bond between our Lord and his people.” He then proceeds to describe the benefits of being in Christ. There is truth here, but something feels thin. The language begins to sound less like a living relationship and more like a description of belonging, almost like a kind of membership, as though these are the benefits of being “in the club,” rather than the reality of a shared life with God Himself.

Ferguson addresses the idea that Paul may have borrowed from the mystery religions of his time, and rightly rejects it, pointing instead to roots in the Old Testament. He focuses primarily on a covenantal or representative understanding of being “in,” using examples like David’s victory over Goliath, where David’s triumph becomes Israel’s triumph. That is certainly a valid dimension of the Old Testament, but it is not the whole picture. What seems to be missed is the depth of personal relationship that is also present. The Old Testament does not only give us corporate representation, it gives us real encounters with God. Moses speaking with God face to face, Jacob wrestling through the night, Abraham walking in covenant. These are not merely examples of shared outcomes or collective identity. They reveal a lived, relational, and deeply personal engagement with God that goes far beyond what might be described as the benefits of belonging.

Ferguson then highlights Jesus’ own teaching, noting, “He speaks of the disciples’ union with one another being as close as his own union with his Father, because based on their union with him (John 17:23, 26).” This is a crucial moment. The obvious implication, which seems to be passed over too quickly, is that the relationship between Jesus and His disciples reflects something of His relationship with the Father. This is where Gifford’s concept of a third type of perichoretic relationship becomes so illuminating. Yes, there is a close relationship among believers, and yes, it is mediated through Christ by the Spirit. But more than that, we are drawn into a relationship with God that is, in some real sense, like the relationship within the Trinity itself.

Ferguson lists several analogies used in Scripture to describe this union, including head and body and marriage. These are helpful, but he does not mention familial adoption, which is also deeply significant. Gifford, in contrast, gathers these analogies and shows how they point beyond themselves toward something deeper, something that aligns with participatory union in the life of God.

When Ferguson turns to the nature of union with Christ, he is careful to avoid misunderstanding. He notes that the term “mystical” is too broad and often misunderstood. He writes, “Often ‘mystical’ suggests the idea of a merging between oneself and God. But union with Christ should not be thought of in terms of a loss of our own identity.” He is absolutely correct. This is precisely why the framework of a third type of perichoretic relationship is so helpful. It preserves the Creator and creature distinction while still affirming a real and profound union, much like the second type of perichoretic relationship seen in the hypostatic union of Christ, where two natures are united without confusion or separation.

Ferguson then outlines six characteristics of union with Christ. A federal union, a carnal or flesh union, a faith union, a spiritual union, an extensive union, and a union of life. Each of these contributes something, but taken together, they still feel incomplete.

• Federal union — Christ or Adam as our covenant head, with a sense of inclusion in an agreement.
• Carnal or flesh union — this is the hypostatic union of Christ, fully God and fully man, two natures united in one person without mixture or division.
• Faith union — spiritual blessings are ours when we are in Union with Christ.
• Spiritual union — the work of the Holy Spirit carrying us into Christ, yet described so briefly that it is difficult to grasp fully.*
• Extensive union — the idea that this union touches all of human experience.
• Union of life — again emphasizes the benefits of life in Christ, though the language leans more toward what we receive than what we participate in.

*This echoes Jacob Chengwei Feng’s observation that the role of the Spirit is often underemphasized in discussions of union.

To his credit, Ferguson does move in a stronger direction when he speaks of transformation. He writes, “But when we are joined to him there is also a sense in which his life and power become available to us to transform our lives.” This is important. He rightly points toward becoming Christlike, and he also acknowledges the cost of union with Christ, that we are united with Him in both His death and His resurrection.

He concludes with the fruit of this transformed life, saying, “Through union with Christ in his death comes union with him in his resurrection and a share in his triumph.” There is real beauty here, and real truth.

And yet, stepping back, I cannot escape the sense that Ferguson is orbiting at a distance from the full reality of what it means to be in Christ and for Christ to be in us. There are strong points throughout, but the overall picture lacks the depth of relational participation that others, such as Gifford, Dallas Willard, or Major Ian Thomas, begin to describe. The language remains cautious, perhaps too cautious, and in doing so it seems to stop short of the full, living, dynamic reality of union with God.

Which leaves us with a question worth sitting with. If union with Christ is as central, as profound, and as practical as Ferguson himself affirms, then how far does it really go. And are we willing to follow it all the way there?

References

• Feng, J. C. (2023). Pneumasis/pneumafication based on Romans 8:1–17. Religions, 14(9), 1210. https://www.mdpi.com/2077-1444/14/9/1210
• Gifford, J. D., Jr. (2011). Perichoretic salvation: The believer’s union with Christ as a third type of perichoresis.
• Thomas, W. I. (Major Ian Thomas). (1961). The Saving Life of Christ. Zondervan.
• Willard, D. (1998). The Divine Conspiracy: Rediscovering our Hidden Life in God. HarperCollins.
• Willard, D. (2012). Hearing God: Developing a conversational relationship with God (Rev. ed.). IVP Books.

Excerpt

Ferguson rightly calls union with Christ central, yet his treatment feels more like belonging than participation. What if union is more than covenant status or shared benefits, but a real, lived participation in the life of the Triune God?

ὑμεῖς ἐν ἐμοί, κἀγὼ ἐν ὑμῖν