Doctrine — Theology With Its Boots On
You believe in Christ. Most who read this site do. You can sign the doctrinal statement, walk the aisle, list the five solas, and recite John 3:16 from memory. That sentence — I believe in Christ — is the front door of the Christian life.
But there is another sentence in the New Testament that gets used roughly two hundred and twenty times, and you have probably never preached a sermon on it. In Christ. Sometimes in Him. Sometimes in the Lord. Two words, repeated more often than almost any other phrase Paul writes. And they are not interchangeable with I believe in Christ. They mean something different, and the difference is most of your sanctification.
Believing in Christ tells you something about you. Being in Christ tells you something about where you are. And until you understand the second one, the first one will feel like a permission slip you keep losing.
The Phrase Paul Cannot Stop Saying
Open Ephesians and watch what happens in the first fourteen verses.
“Blessed be the God and Father of our Lord Jesus Christ, who has blessed us with every spiritual blessing in the heavenly places in Christ, just as He chose us in Him before the foundation of the world… In Him we have redemption through His blood… In Him also we have obtained an inheritance… In Him, you also, after listening to the message of truth, the gospel of your salvation — having also believed, you were sealed in Him with the Holy Spirit of promise.”
Ephesians 1:3–4, 7, 11, 13 (NASB1995)
Eleven times in fourteen verses. In Christ. In Him. In Him. In Him. Paul is not being repetitive. He is hammering on a load-bearing wall. Every spiritual blessing — every one — is delivered to the believer by being placed inside of Christ. The blessings are not handed across the table. They are inherited from inside the family.
This is the doctrine that Reformed theologians call union with Christ, and it is the doctrine sitting underneath nearly every promise you have ever tried to claim.
Three Ways a Branch Belongs to a Vine
Christ Himself taught the doctrine in John 15. Not in propositions. In an image.
“I am the vine, you are the branches; he who abides in Me and I in him, he bears much fruit, for apart from Me you can do nothing.”
John 15:5 (NASB1995)
Look at the picture. A branch is not nearby the vine. A branch is not endorsing the vine, or working for the vine, or grateful to the vine. A branch is part of the vine. Sap from the trunk is sap in the branch. Life in the root is life in the leaf. The branch does not need to get life from the vine — it already has life because it is the vine, extended outward.
That is what Paul is doing when he says in Christ. He is telling Christians that what is true of Jesus is now, by virtue of grafted-in union, true of them. There are at least three layers of that union worth seeing clearly.
- Legal union — Christ as your representative. What happened to Christ on the cross legally happened to you. What happened to Christ on the third morning legally happened to you. The court of heaven does not look at you and decide. It looks at Christ and counts.
- Vital union — Christ as your life. The Spirit who indwelt Christ now indwells you. The same resurrection power that walked Him out of the tomb is the operating power inside you. You are not living next to Him. You are living from Him.
- Eternal union — Christ as your destination. Where Christ has gone, you are going. What He inherits, you co-inherit. The promise is not that you will one day reach Him. The promise is that you are already where He is, and where He is going you cannot fail to arrive.
Take any one of those three away, and the Christian life shrinks down into a self-improvement project with religious vocabulary. Hold all three together, and the whole New Testament starts to make sense in a way it did not before.
The Two Sentences That Should Stop You Cold
If union with Christ is real, then two sentences in Paul are no longer poetic. They are accurate.
“I have been crucified with Christ; and it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself up for me.”
Galatians 2:20 (NASB1995)
“For you have died and your life is hidden with Christ in God.”
Colossians 3:3 (NASB1995)
Read those slowly. I have been crucified. Past tense. Already done. The “I” who used to run the show is, according to the New Testament, a corpse. You have died. Past tense again. The center of your identity is not a struggling self trying to become better. It is a hidden self, tucked into the life of the risen Christ, in the presence of the Father, beyond the reach of any accusation.
This is not motivational language. This is doctrinal anatomy. Paul is describing where you actually are. Not where you should aim to be after enough quiet times. Where you are.
Why So Many Christians Live as if This Is Not True
Here is the diagnostic question. Does your daily walk feel like a man trying to earn his way toward Christ, or like a man living from Christ?
The two feel almost identical at the surface. Both involve prayer. Both involve Bible reading. Both involve obedience. But underneath, they are different planets. The first man is performing in the hope that his performance will close a gap between himself and God. The second man is responding from a gap that has already been closed.
One is exhausting. The other is freedom.
And the difference between them is union with Christ. The first man does not know — or has not let himself feel — that he is already in. He is acting from outside the door. The second man knows he is inside the house. He prays as a son, not as a petitioner. He reads as someone listening to his Father, not as someone trying to earn a hearing.
If your Christian life feels heavy, repetitive, joyless — that is often the first symptom. You have left the doctrine of union sitting on the shelf, and you are working very hard to do from outside what God has already given you from inside.
What This Doctrine Will Not Let You Do
Union with Christ also refuses some things that a softer theology will let you have. Three of them are worth naming.
- It will not let you despair. If you are in Christ, your standing is not built on your last week. It is built on a resurrection two thousand years old. Despair is theologically illiterate for the believer. You may grieve. You may repent. You may sit in the consequences of what you have done. But you may not despair, because you are not the one holding yourself there.
- It will not let you compare. Comparison is the sport of men who do not know where they stand. Once you know you are in Christ, the man next to you also being in Christ does not threaten you. His blessings are not subtracted from your account. There is no shortage of inheritance inside the Son of God.
- It will not let you stay in sin. Paul says it plainly in Romans 6: how shall we who died to sin still live in it? If you are in Christ — really in Him, really united to His death and resurrection — then sin no longer fits. It is the old garment of someone who used to live here. Union does not give you permission to indulge. It gives you the only ground from which sin can finally be put down.
“In Christ” Is the Reason Stage Four Is Possible
For the man walking the path of restoration — writing the apology he owes, facing the wreckage of years he cannot recall — this doctrine is not abstract. It is the only ground he can stand on.
Because here is the question every honest confession eventually asks. Who am I, now that I have said it out loud? If your identity is built on your performance, that question is unanswerable. You are the worst sentence you ever spoke about yourself.
But if you are in Christ, the answer comes from a different place entirely. You are the man whose old self has been crucified with Him. You are the man whose new self is hidden with Christ in God. You are the man who can say the worst thing he has ever done in a clear sentence and not collapse, because the sentence is not bigger than the union.
“Therefore if anyone is in Christ, he is a new creature; the old things passed away; behold, new things have come.”
2 Corinthians 5:17 (NASB1995)
Notice the condition. If anyone is in Christ. Not if anyone tries hard. Not if anyone has cleaned up. The new creation is a function of location, not performance. You are made new because of where you stand, not because of how well you have stood.
Where to Put This in Your Week
Doctrine is theology with its boots on, which means it has to walk into a Tuesday. Here is what union with Christ looks like in the ordinary middle of the week.
- When the accusing thought lands — after what you did, you should not even be praying — you answer it not by arguing, but by remembering location. You are in Christ. The accuser is shouting at the wrong man.
- When the pull of an old pattern shows up, you do not white-knuckle. You stand inside who you actually are. The old self is dead. The new self does not want this. You are not denying yourself a pleasure; you are refusing to dress in a corpse’s clothes.
- When obedience is hard, you do not grit your teeth. You ask the question Paul keeps asking: do you not know what you are part of? The Christ in whom you are placed already lives in willing obedience to the Father. The branch is connected to the vine. The fruit will come because of who you are, not because of what you can squeeze out.
Two words. Used roughly two hundred and twenty times in the New Testament. Sitting underneath every promise you have ever read.
In Christ.
The Christian life does not get any heavier than the man who has not yet seen them. And it does not get any freer than the man who finally has.
Teaching the Word. Watching the Times. — SmithForChrist