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What Is Union With Christ? Dr. Nathan Tarr

Phoenix Seminary
October 4, 2022

Dr. Arnold interviews Dr. Tarr on what it means to be united with Christ.

Topics of conversation include:

  • What we mean when we use the phrase “in Christ”
  • Why union with Christ is a foundational to understanding the gospel
  • How a person becomes united with Christ
  • The relation of suffering to being in Christ
  • The corporate aspect of union with Christ
  • A resource for further reading on this subject

Dr. Nathan Tarr is associate professor of Pastoral Theology and the Doctor of Ministry program director at Phoenix Seminary. He holds a PhD in Biblical Spirituality from The Southern Baptist Theological Seminary, and previously planted Christ Church in Knoxville, TN, and served as associate pastor of Discipleship and Missions at Christ Baptist Church in Raleigh, NC.


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Intro (00:00):

Welcome to Faith Seeking Understanding, a podcast from Phoenix Seminary—helping Christians grow in their understanding of the faith, hosted by Dr. Brian Arnold, president of Phoenix Seminary.


Brian Arnold (00:17):

In Romans chapter six, the Apostle Paul writes, "What shall we say, then? Are we to continue in sin that grace may abound? By no means! How can we who died to sin still live in it? Do you not know that all of us who have been baptized into Christ Jesus were baptized into his death? We were buried therefore with him by baptism into death, in order that, just as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life. For if we have been united with him in a death like his, we shall certainly be united with him in a resurrection like his. We know that our old self was crucified with him in order that the body of sin might be brought to nothing, so that we would no longer be enslaved to sin. For one who has died has been set free from sin.


Brian Arnold (00:57):

Now if we have died with Christ, we believe that we will also live with him. We know that Christ, being raised from the dead, will never die again; death no longer has dominion over him. For the death he died he died to sin, once for all, but the life he lives he lives to God. So you also must consider yourselves dead to sin and alive to God in Christ Jesus." One of the most profound mysteries of the Christian faith is this idea that we are united to Christ by faith. It's a truth that so few seem to know, and even less appreciate—that we are in Christ, and Christ is in us. Today, to help us understand union with Christ, we have with us Dr. Nathan Tarr. Dr. Tarr is Phoenix Seminary's new associate professor of Pastoral Theology and the director of our Doctor of Ministry degree program. He holds a PhD in Biblical Spirituality from The Southern Baptist Theological Seminary. Dr. Tarr has published on topics in Church History and Christian Spirituality, and previously taught courses on Preaching and Pastoral Theology at Southeastern Seminary. Dr. Tarr also helped plant Christ Church Knoxville in Knoxville, Tennessee, where he served as lead pastor for 13 years. Dr. Tarr, welcome to the podcast.


Nathan Tarr (02:07):

Thanks Brian. It's good to be here.


Brian Arnold (02:09):

So as you know, we ask our guests one big question. Today the question is going to be—what is union with Christ? And here I think we need to start with the definition. That might even be a phrase that's new to some people who are listening. What do we mean when we say "union with Christ"?


Nathan Tarr (02:22):

Right. Well, it's a massive idea. Not only because it's all over Scripture, but because of how rich it is. But I think maybe the most simple and straightforward way to define it would be when we talk about union with Christ, we're talking about the richness and the fullness of our relationship between the believer and Jesus Christ.


Brian Arnold (02:44):

So as we think about the doctrine of salvation and we as theologians, we'll use the big Latin phrase ordo salutis, this order of salvation, where one is justified, sanctified, and ultimately glorified in Christ. Where does union with Christ kind of fit into that idea of the ordering of salvation?


Nathan Tarr (03:05):

Right. So maybe we could picture union with Christ as kind of the fountain head out of which all of those blessings of our salvation—our justification, our adoption, reconciliation, sanctification, you mentioned—all of those flow out of this one central good, or source of our salvation, which is the fact that we are united to Christ. I'm thinking here, for example, of like Ephesians 1:3, where Paul celebrates every spiritual blessing that is ours in the heavenly places, but all of those blessings are ours in Christ.


Brian Arnold (03:47):

Which is a phrase that occurs a lot of time in the New Testament. I think some people read their New Testament and probably don't catch the beauty of some of these prepositions in the text—that we are in Christ, we are with Christ. You know, 76 times in the New Testament, we read that we are in Christ. So help us even understand what that means in terms of like, am I literally in Christ? Is that a metaphorical thing? Is it spiritual? What does it even mean, if I can say this, like, spatially even to be in Christ?


Nathan Tarr (04:17):

Yes. Because Paul talks mentioned the with Christ language. I think we heard some of that in Roman six. We hear it in Ephesians two, again, this idea that we have died with Christ, we have been raised up together with Christ, we are seated together in the heavenly places with Christ. And so there does seem to be some kind of spatial or bodily component to the idea. But I think the reason it is so significant, and Paul mentions, not only the 76 times of in Christ, but I think I've heard a number as high as like 216 when we're taking into account all of the different ways that we are related to Christ in Paul, this is obviously a massive idea of a really a central foundational idea for him.


Nathan Tarr (05:10):

And I think the reason why is because this really is shorthand for the gospel itself. I mean, what we get when we get salvation is nothing short of Christ. We get Jesus, and in Jesus we get entrance into the life of the Triune God. And so this is a great thing. This is, you know, I said, the source of all of those other blessings of salvation, and I think that's what makes it so key. And I say all that as a way of getting around to your question of like—how do we understand this? Because I want to say, yes, it's spiritual, but only if we don't mean by spiritual, you know, imaginary, or like just an analogy or, you know, just a doctrine, just kind of an idea. It's spiritual, but that doesn't mean it's less real.


Nathan Tarr (06:08):

I mean, we are really, in some cases...there's a way that, bodily, we are in Christ. And I'd love to hear your follow up on this, but maybe I'll just say one more thought pointing us to Roman six, the passage you read. We have...whatever we think of when we think about being in Christ, it has to be able to account for the fact that Paul says, in effect, what has happened to the body of Christ. For example, he's died. He's been baptized, you know, into that, through death, is now part of our spiritual testimony, right? We too have been baptized, we have died with Christ and been raised with Christ, baptized into that death. So that's what I mean when I'm talking about physical, is that it...what's true of Jesus has become part of our...the testimony, you know, of God's work in our own life. And so our definition of union with Christ has to be able to account for that.


Brian Arnold (07:14):

There's some really important things that you're mentioning there—as union with Christ as a bit of a synopsis of what the gospel even means. That whatever's true of Jesus is now true with us because we are united to him. What does it mean to be saved? It is to be covered by the blood of Christ. It is to be in relationship with the Lord Jesus Christ. You've alluded to Ephesians chapter two. And I actually just...I want to read this. You know, I hear from some of our guests, and they use this as a podcast, even with their kids, as they're driving back and forth to school. And I imagine some people are listening to this—many, many people are listening to this who are in just some sort of struggle right now in life, wondering—where is the Lord right now? And I just want to give this as a word of encouragement, since you mentioned this passage, is Ephesians chapter two, which verses one through 10 are some of the greatest verses for understanding the gospel.


Brian Arnold (08:01):

So Paul has already indicted us all in sin. What hope do we have? And then in verse four, "But God." Which is the sweetest two words, probably in the whole Bible. It is bleak. It is a bad situation—"But God, being rich in mercy, because of the great love with which he loved us, even when we were dead in our trespasses, made us alive together with Christ—by grace you have been saved—and raised us up with him and seated us with him in the heavenly places in Christ Jesus." So a couple "with hims" and "in Christ Jesus," and "where are you right now?" So whatever struggle you find yourself in life, Paul is using this as a past tense idea—that we are to consider ourselves as already seated with Christ. What a glorious truth. I mean, we can really, as the old hymn, right, said, you know, we can face tomorrow, because of what we know of Christ. So Nathan, I mean, this is the 64 million dollar question. How does one get that relationship in Christ? How does one become counted in Christ?


Nathan Tarr (09:03):

Yeah, that is the question. And I think, you know, the answer...Scripture uses different language to describe it. One of the ways Scripture talks about how we are united to Christ is through faith. So our faith unites us to Christ. Or the Spirit, like in Roman six or in Galatians three, the Spirit baptizes us into Christ when we are given the gift of that soft heart. Or the Scripture talks about Christ, for example, taking hold of us. We talk about, you know, Christ baptizing us with his Spirit in the same way that we may talk about the Spirit baptizing us into Christ. That's not the Bible talking out of both sides of its mouth, or being unclear about what it means.


Nathan Tarr (09:58):

What's happening there...the Puritans, for example, picture this as like, you know, two hands grasping each other from opposite directions. Christ is taking hold of us and uniting us to himself by his Spirit. And we...the Spirit is helping us reach out and grasp, trust Christ, be united to Christ, through our faith. And so, you know, the short answer is we believe in Jesus, and we're therefore united to him by our faith. But we should maybe remind ourselves that this is happening, because at the same time, Christ is laying hold of us. And, as he promises in John 10, will never let us go.


Brian Arnold (10:39):

And I think that's helpful for somebody listening who's wondering—okay, I put my faith in Jesus, but when do I get that united with Christ part? That is what happens at the moment of salvation. You are united to Christ. And, as you mentioned in John 10, never to be separated from him. I mean, this is the beautiful doctrines of even election, where God is reaching out and pulling us from sin, and then holding us forever, what we might call perseverance. Is he is the one who, from beginning to end, is acting for our salvation. You had mentioned something there that I thought is really significant, because I think when people conceive of salvation and what it means now to be in Christ, we think about the Holy Spirit. We think about the indwelling presence of the Holy Spirit. But now we're reading—we're in Christ. Christ is in us. So how is it that Christ is in us? We are indwelled by the Holy Spirit. So help us understand that.


Nathan Tarr (11:33):

Well, it is a mystery in the sense that even Scripture piles lots of different kinds of phrases up...I'm thinking, for example, of the way Paul talks just a few chapters later in Romans eight, and verse nine in an attempt to explain how rich and wonderful this is. But I'll give it a shot. You know, the testimony of Scripture is that, for example, Romans 8:9, the Spirit of God dwells in us, Paul calls it, and then in the next verse calls it the Spirit of Christ dwelling in us. Again, that's not confusion, because he goes on to talk about Christ being in us and us being in Christ, rather than Christ dwelling in us, rather than us being in the flesh and living under the old master that you just read about there in Ephesians chapter two. Jesus, in John 17, does the same kind of thing, piling up these ideas, where he's praying to the Father that those who believe in him would be one, just as—which is really a remarkable phrase—just as you, Father are in me and I am in you, they may be in us.


Nathan Tarr (13:00):

And so I think that the simplest way to say this, but it is the most wonderful way, is to repeat what I said earlier when I...what's happening in union with Christ, again, is not that we're getting a thing or a piece of salvation. It really is that we are being invited into the life of God, into the love of God. The life of the Triune God, the love of the Father for the Son, and the power of the Holy Spirit. And so Scripture will talk about that richness of life, what C.S. Lewis called "illimitable life." There's just not one phrase that does it justice. And so talk about Christ being in us, God being in us, the Spirit being in us. And yet, really what's happening here, is by the Spirit, through Christ, we are being granted access into the life of God.


Brian Arnold (13:59):

And it's not insignificant to say, as you mentioned, John 17, for those who may not know, what's immediately preceding that—Jesus is in the upper room, he's talking with his disciples about his near departure, and he gives them the comfort that the Paraclete, the Holy Spirit, the helper, is going to come. And that it's good for him to go. So, as Jesus says, what is it like for him and the Father to be one? And what is it like for us to...I like how you even pull out the—what we hear in tradition, right? Like we're entering into the life of God by our union with Christ. This mystical union with Christ is really entering us into the life of God. It's just an amazing aspect of the Christian life that so many people don't think about. You just don't hear a lot of sermons about this.


Brian Arnold (14:48):

You don't hear people dwelling on this topic. I can think of one theologian who gets a lot of bad press by a lot of people, is John Calvin. I think people think John Calvin just went around saying, "You're predestined! You're not predestined!" Like that's the only thing he ever thought about, which actually doesn't make up the lion's share of his theology at all. But he is fundamentally concerned about the doctrine of union with Christ, and how all doctrine and all of our Christian life centers back into that one beautiful idea from Scripture—that we get to participate in the life of Christ.


Nathan Tarr (15:19):

That's right. And the Luther was huge on this, as was Calvin, as were there eras in the Puritans. I mean, this was—if I can say it this way—this is what they got most excited about. And you know, if union with Christ is something that we are not as familiar with, it's probably because we have made much of those—what Ephesians 1:3 calls—spiritual blessings. We praise God for our justification, for example, or like, you know, like J.I. Packer reminds us—we want to make much of our adoption, that we're sons and daughters of God, that we can cry out to him, the Spirit helping us, using the very same words of Jesus, and all of these wonderful things—we want to press on in our sanctification, and increasingly conform our character to the character of the beautiful Son of God.


Nathan Tarr (16:14):

All of these things are really important. And that's where a lot of times our emphasis falls. And perhaps we forget that those all flow out of this central good of our salvation, which is that we're united to Christ, and in Christ are part of God's very life. You really can't get any better than that. And it' can't say too much about it, which I think is why we find Paul returning to this language over and over and over again, as he celebrates what God has done in Jesus.


Brian Arnold (16:46):

Well, what you said earlier is union with Christ is kind of the idea that sits above—or you said the source of—all these other beautiful doctrines on salvation that we talk about. And we've listed many of them already—you just mentioned these privileges we have of being in Christ and what that means, but there's also some sobering implications of this as well, isn't there? Because Paul, and even Peter, talks about these ideas that, because we're in Christ, that's going to mean suffering as well. So why don't you talk about the flip side of that, too, of what does it mean that if we're in Christ, we don't even just receive all those blessings, but there's also a suffering component. And that's not meant merely as a negative thing, right? Paul actually has some positive implications of that.


Nathan Tarr (17:26):

That's right. And so here we need to be willing to adjust our definition of what is good, in the sense that we would often define, you know, a lack of hardship, a lack of suffering, easy circumstances—that for many of us, that's what it would look like if God was doing good for us. The Bible operates with a little bit of a different understanding of what is our good, namely that, for example, in Romans 8:28, you know, what is good, and the good for which God is working everything in our life, even and especially those hard things, is that we are being conformed to the character of Christ. And so, yes, this is a part of being in Christ, of following Christ, of Christ being the head of the body, in the sense of—we follow in his steps, him being our Lord, a servant not being greater than our master, is that we will go through suffering.


Nathan Tarr (18:28):

We live in a...yes, in a way, Ephesians two is true. We're seated with Christ in the heavenly places, but it's also true right now that we are here in this fallen world. And so our hope is not here, but our body is here. And we are having to engage the slings and arrows of a fallen world, and the accusation that comes against followers of Christ in this kingdom and this economy. And so, that is a sobering implication of our union with Christ, is that we will suffer, even though Paul says in Romans five that we can rejoice in those sufferings, because ultimately it's proving our character, as it creates endurance and causing that hope that we have in Jesus to be all the more sure. But I might just add, as we're thinking about the difficult side of being united to a crucified Savior, is that our union with Christ means that not only we'll walk through the Valley of the Shadow of Death, but that he'll be with us in those dark and hard places.


Nathan Tarr (19:34):

He doesn't abandon us. He doesn't come and go. He doesn't, you know, kind of wait for us on the other side, but he's in us, he's within us, as our very life. And so he doesn't forsake us, and he gives us the strength to endure and often ministers his love to us in a most significant way in those challenging times.


Brian Arnold (19:55):

It's the only way to really be made into the image of Christ, is suffering. Like you...I love the passage you mentioned, that the servant is not above his master. If the master suffered, you're going to suffer too. I think about Philippians 1:29, "For it has been granted to you, that for the sake of Christ you should not only believe in him, but also suffer for his sake." It's granted to us—we think about Peter and John rejoicing that they were found worthy to suffer for the name of Christ. These are not delusions or something that they're experiencing at this time. This is really understanding that Christ is going to call us to suffer. He is the fourth one in the fire. He's not leaving us alone. He's not abandoning us. He's not forsaking us, like you mentioned.


Brian Arnold (20:37):

But he really is using these trials in our life for our good, because we cannot be really made into the image of Christ without walking through life's sorrows and suffering and challenges. So, dear believer, don't feel abandoned by God in these seasons. Don't feel forsaken. Feel like you have a God who is with you. You are in Christ. And because you're in Christ, he is by your side, no matter how deep the valley gets. I think that it's actually a beautiful side of what it means to be in Christ, is that we are going to be able to be shaped by the challenges of life and the hardships to be more like him. So what is this union with Christ idea? We've talked a lot about kind of this vertical relationship of what it means to be in Christ, and what that does with our relationship with God. What does it do for our relationship with others? What's the horizontal aspect and implications of our union with Christ?


Nathan Tarr (21:37):

Right. Something...another aspect we may not think about in our culture that tends to think very personally and individualistically about our salvation. But, you know, if we think even about the metaphors that Scripture uses to describe our union with Christ, they're corporate—the vine and the branches, right? Many branches next to one another, growing out of that vine. The head and members of the body, may be the most clear—that we are only members of an entire body, that is in the head. The husband and wife imagery that Paul uses in Ephesians five, that the Puritans and the Reformers love to use—this idea of this "mystical marriage" they called it, between the believer and Christ, as a way of picturing union.


Nathan Tarr (22:28):

You know, Scripture makes it clear—this is not an individual that comprises the bride, but it's a corporate bride. It's all of the believers. And so yes, there are corporate implications of our being united to Christ. We are in Christ, but so too is everyone else who believes on him. And so, in that sense, we're related one to another. You know, if I could say it probably the most provocatively, I might say it like this—you know, salvation, like my salvation, and the church—gathering together corporately with believers—those are two sides of the same coin. Those are two sides of that same reality of being united with Christ. On the one side, I am united to Christ and there's the source of my whole salvation, not just now, but forever. But on the other side of that coin, the doctrine of the church also rests on that reality of being united—believers united together into God in Christ.


Nathan Tarr (23:32):

And so it's inescapable. And it presses us out in love and patience and service for our neighbor. The way Luther said it—Luther loved to put things provocatively, you know—but he said, "We live in Christ through faith, and we live in our neighbor through love." So basically, because Christ has given of himself to us the way that he has, and we have everything we need before God in Jesus, we are free to turn, then, and spend ourselves, not piling up good works for our own salvation, but in service of our neighbor. So that's the way he relates our being in Christ to our living—if I can change his language a little bit—our living for the sake of one another. Like Paul talks about it in Philippians 2, considering others better than ourselves. That is an inescapable part of being united to Christ.


Brian Arnold (24:30):

Well, Luther always has a way of saying it best, doesn't he? Well, we could say so much more about this beautiful treasure of a doctrine, and if it's new to you as a believer, I hope it's something you'll take seriously to think about, to study. Nathan, could you give us maybe just one resource that people could read that would be really helpful on this?


Nathan Tarr (24:49):

Yes. Seeing some good resources published the last five or 10 years, but probably the top of the list would be Marcus Johnson's book. His book with Crossway called One With Christ: An Evangelical Theology of Salvation.


Brian Arnold (25:01):

Well, fantastic. I hope people will get that, read it, and learn what beautiful treasures there are in knowing that once we are in faith, we are united to Christ. And we're going to be united to Christ forever. Dr. Tarr, thank you so much for this conversation today.


Nathan Tarr (25:15):

You're welcome, Brian,


Outro (25:16):

Thank you for listening to Faith Seeking Understanding. It means so much to us that this content is helping you grow in your understanding of the faith. I want to take a moment to tell you about our new online learning experience at Phoenix Seminary. Over the last year, we've been creating what we believe to be the highest quality of online courses for ministry training. If you're called to train for a lifetime of faithful service, but can't join us on campus, I'd like you to invite you to join us online. Take courses featuring some of the guests you've heard on Faith Seeking Understanding, including Wayne Grudem, Mike Thigpen, Steve Duby, myself, and more. Learn more about Phoenix seminary online, and even access the entire online lecture content for my church history course at

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