What Does It Mean That Believers Are United to Christ?

Understanding our union with Christ is fundamental to understanding our identity as Christians. Today, Sinclair Ferguson illustrates the spiritual union that we share with our Savior.

NATHAN W. BINGHAM: Joining us this week for the Ask Ligonier podcast is Dr. Sinclair Ferguson. Dr. Ferguson, what does it mean that believers are united in Christ?

DR. SINCLAIR FERGUSON: What does it mean when we say that believers are united to Christ? Well, first of all, I think it is really helpful for us to understand that in the New Testament, this idea of being united to Christ is absolutely fundamental to how the New Testament Christians understood themselves.

I think it’s really surprising that we can be reading the New Testament for years and not actually notice this, but as soon as we notice it, we begin to see it everywhere. And what I mean by saying that is that the most common way of describing a Christian in the New Testament is to say that he or she is “in Christ.” And especially in Paul’s letters, once you’ve noticed that little expression once, you see it in almost every paragraph, scores and scores and scores of times—so much so, I’ve sometimes said it’s doubtful that the early Christians describe themselves as “Christians.” It looks as though that was a slur word, almost hate speech in the New Testament days. But they did constantly think of themselves and each other as being in Christ. So, how can we understand that?

One helpful way, I think, is to remember that the New Testament teaches us that by nature we are in Adam. So, Paul speaks about this in Romans 5:12–21. He speaks about it in 1 Corinthians 15. How are we in Adam? Well, we’re in Adam by representation. He was the head of the whole human race. He was what we sometimes call the covenant head or the federal head, so that what he did had implications for us. He was our representative. And so, the decisions that he took, especially the decision to grieve the Lord and sin and take the forbidden fruit, that was an action he did not just for himself but also on behalf of us. And then, secondly, we are in Adam by participation, because we share in Adam’s human nature. And so, on the one hand, we are caught up in Adam’s sin and guilt, and on the other hand, that sin and guilt is reproduced in our lives too.

But now, through Christ, we’ve been brought out of Adam into this new family, into Christ’s family. And the New Testament, as I said, says over and over again that we are now in Christ. In fact, sometimes the New Testament uses rather special language when it says that we believe into Christ. We actually believe into union and communion with Christ. Now we know that that is something God planned from before the foundation of the world. Paul says that in Ephesians 1.

So, we are in Christ in the mind of God by election, but then we’re also in Christ by representation. He has come to be the second man and the last Adam. He is our representative. And because He is our representative, He has taken our flesh. He’s lived our lives, He’s died our death, and He joins us to Himself now so that there is a spiritual participation, whereas we have a natural participation with Adam because we are all descended from him. We’re not all descended physically from the Lord Jesus. In fact, interesting, isn’t it—no one is descended physically from the Lord Jesus. So, we come to participate in all that Christ has done for us not because we share in the kind of participation that we all share with Adam but because we share with Him through the Holy Spirit.

And this is really the amazing thing that we’re united to Christ through the Holy Spirit. And that union is so close that in that union, He actually gives us His Holy Spirit. We are indwelt by the same Spirit who indwelt the Lord Jesus. Sometimes the Bible uses marriage as an illustration of this. But even the intimacy of the very best and longest marriages kind of pales into significance by comparison with this union in which we’re united to the Lord Jesus because we’ve actually come to receive His Spirit. We couldn’t possibly be more closely united to Him than that. And when we see that, I think, then there’s so much else in the New Testament that opens out, and we are able to say with Paul: “I’ve been crucified with Christ, and yet I live. And the life that I live now, I live by faith in the Son of God who loved me and gave Himself for me” (see Gal. 2:20).

So it is a great and really very important teaching of the New Testament for us to keep reflecting on and to live in the light of.