Deologian Michael Reeves joins us one more time from the UK, filling in this week for John Piper. Michael, you've written and spoken a lot about union with Christ over the years. So why is it important for Christians to understand and embrace the precious truth of union with Christ? And what's lost if we don't understand it?

What's important about union with Christ for the Christian life? Well, union with Christ, Tony, is the Christian life. So it's not some small particular blessing that might go alongside the key blessings of the gospel. Union with Christ is the Christian life. And I think there are a couple of pictures.

Let's try to understand what this is that we're talking about. There are two main pictures that Scripture gives us. The first comes up in Romans 5 and in 1 Corinthians 15. Let's have a think about the 1 Corinthians 15 example. Paul writes this. He says that "as in Adam all die, so in Christ shall all be made alive, each in his own order.

Christ the firstfruits, then it is coming those who belong to him." So what he's got in mind is that everyone is in either Adam or Christ. No one is a self-determining individual. There is no such thing. You find your identity in either Adam or Christ. And the picture he uses in 1 Corinthians 15 to explain that, this "in Adam, in Christ" language, is that of the firstfruits.

He sees Adam and Christ as the firstfruits of two different sorts of humanity, the old humanity and the new. And I think what's being picked up there is Genesis language, where the firstfruits of creation on day three of Genesis, Genesis 1, you see the fruits there have seed within them.

And so just as a seed is found within the fruit, so where you take the fruit and what you do with it happens to the seed, the seed goes wherever the fruit goes. So it is with Adam and Christ. If you're in Christ, you find your identity and status in him.

You're like seed in the fruit. You need to be taken out of Adam and regrafted, born again in Christ. And that means that if that's the case, if we found our identity as Christians in Christ, I found this to be a revolution in my own Christian life. That when I came to understand union with Christ, I saw, so then I do not stand naked before a holy God based on my own pathetic performance.

I stand clothed in Christ, clothed in him. That's language that gets picked up a few times in scripture. There's the first image that gets used of union with Christ. There's another very, very important one, which is marriage. And this is really Ephesians 5 territory. So where Paul writes, "For this reason, a man will leave his father and mother and be united to his wife and they'll become one." And then Paul says, "This is a profound mystery, but I'm talking about Christ and the church." He's saying that the relationship the church has with Christ is a marital union.

Now, actually, Martin Luther used this image as the first way in which he articulated his Reformation discovery in 1520. He used marriage to explain the gospel to the world for the very first time properly. It's in a little work called "The Freedom of a Christian." And he said, "What happens is this, that it's rather like the story of a great king marrying a harlot.

And what happens is this harlot can't make herself the great king's wife by anything she does or her performance, but by his wedding vow, she becomes his." And he says to her, "All that I am, I give to you. All that I have, I share with you." And so gives to her the status of royalty and all that is his.

And she turns to him and says, "All that I am, I give to you. All that I have, I share with you." And so the poor sinner shares with King Jesus all her sin, all her death, all her damnation. And when Luther had articulated this, he said, "Therefore, the sinner can consider her sins in the face of death and hell and say, 'If I've sinned, yet my Christ who is mine has not sinned, and all his is mine, and all mine, my sins, my death, my damnation, is his.'" So union with Christ gives that beautiful life-changing assurance that I can know the Father as my Abba, call with the Son's own cry to him.

But it also changes the very nature of the Christian life, that I've not just been given this package of blessing called heaven. I've been brought to know Christ, and that makes real sense of the Christian life and of holiness. I've not been given some package of heaven to wait for later.

I've been brought to know Christ, meaning when a brother or sister sins, I can say, "Why are you walking away from the salvation to which you've been called?" Knowing Jesus is the only life and liberty for which we've been freely saved. Yes, amen. So what happens when a Christian truly comes to grasp union with Christ for the first time?

I'll tell you my own experience. It meant a freedom from a real despair because I was taking this seriously. I couldn't be sure of how God would look at me until I knew about union with Christ. And it was actually reading Luther's Freedom of the Christian that convinced me of that.

And I saw for the first time I can have confidence before God in Christ, and that brought a freedom to be able to call out to God as Abba. And that liberated me from a suicidal despair for me. Oh, my. Wow, that's incredible. It sounds like a tremendous story to hear.

Unfortunately, we're out of time today. Michael Reeves, thank you for your time this week filling in for Pastor John. I want to remind listeners that Michael has written several books, including The Unquenchable Flame, Discovering the Heart of the Reformation, and the book Delighting in the Trinity. He lives in the UK and currently serves as the director of the online theology website UnionTheology.org and serves as senior lecturer at Wales Evangelical School of Theology.

We are grateful for your time, Michael. Thank you. And we will be back with Pastor John on Monday. I'm your host, Tony Ranke. Thanks for listening to the Ask Pastor John podcast, and have a wonderful weekend.