"Christian" Isn't Paul's Favorite Word for Believers

Did you know the phrase Paul uses most often to describe Christian believers isn't "Christian," "follower of Jesus," or "disciple" — it's the precise theological preposition in Christ?

The Greek phrase is ἐν Χριστῷ (en Christō), sometimes "in Christ Jesus" (en Christō Iēsou), sometimes "in him" or "in the Lord." Across Paul's 13 epistles, the phrase and its close variants appear 165+ times — more than any other theological concept in the Pauline corpus.

For comparison: "righteousness" (dikaiosynē) appears about 67 times in Paul. "Faith" (pistis) about 142 times. "Spirit" (pneuma) about 145 times. En Christō dwarfs all of them. If Paul had to compress the gospel into a single grammatical structure, this is the one he reached for.

The phrase appears in every kind of theological context:

— Romans 8:1 — "There is therefore now no condemnation for those who are in Christ Jesus."
— Romans 12:5 — "we, though many, are one body in Christ."
— 1 Corinthians 1:30 — "And because of him you are in Christ Jesus, who became to us wisdom from God, righteousness and sanctification and redemption."
— 2 Corinthians 5:17 — "Therefore, if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come."
— Galatians 2:20 — "I have been crucified with Christ. It is no longer I who live, but Christ who lives in me."
— Ephesians 1:3-4 — "Blessed be the God and Father of our Lord Jesus Christ, who has blessed us in Christ with every spiritual blessing in the heavenly places, even as he chose us in him before the foundation of the world."
— Ephesians 2:6 — "and raised us up with him and seated us with him in the heavenly places in Christ Jesus."
— Philippians 3:9 — "and be found in him, not having a righteousness of my own that comes from the law, but that which comes through faith in Christ."
— Colossians 2:10 — "and you have been filled in him, who is the head of all rule and authority."

What's striking is the grammatical precision of Paul's vocabulary. He doesn't most often say "follower of Christ" (this would name the believer as the active subject). He doesn't most often say "with Christ" (this would name Christ as companion). He doesn't most often say "for Christ" (this would name Christ as cause). He says in Christ — naming the believer as positioned INSIDE Christ. The believer's identity is a location, not an affiliation.

The Reformed theological category for this is union with Christ (unio cum Christo, sometimes unio mystica). Calvin treats union with Christ as the foundational category of the application of redemption in Institutes III.1-2:

"Christ, when he became ours, makes us sharers with him in the gifts with which he has been endowed. We do not, therefore, contemplate him outside ourselves from afar in order that his righteousness may be imputed to us but because we put on Christ and are engrafted into his body — in short, because he deigns to make us one with him."

In Calvin's reading, every saving benefit comes through union with Christ. Justification is the legal benefit of being in Christ (Christ's righteousness imputed to those who are in Him). Sanctification is the transformative benefit of being in Christ (Christ's life flowing into His members). Adoption is the relational benefit of being in Christ (those in the Beloved Son are themselves beloved sons — see ep60 and ep62). Glorification is the eschatological benefit of being in Christ (where the Head goes, the body follows).

John Murray's Redemption Accomplished and Applied (1955), the definitive 20th-century Reformed treatment of salvation, gives union with Christ its own chapter and treats it as the underlying doctrine that organizes all the other applied benefits of redemption. Sinclair Ferguson's The Whole Christ (2016) develops the Reformed pastoral implications: when you receive Christ, you receive all of Christ — all His benefits — because you are now in Him. You cannot have part of Christ. You either have Him entirely or you do not have Him at all.

The pastoral implication is decisive. The Christian life is not primarily what you do FOR Christ. It is not primarily what Christ does AROUND you. It is what you are IN HIM. Every benefit — forgiveness, adoption, righteousness, the Spirit, eternal life, glorification — flows from your union with Christ, not from your performance.

Christianity isn't an affiliation. It's a location.

You're not next to Christ. You're IN Him.

📖 Passages: Romans 6:11, 8:1, 8:39, 12:5, 1 Corinthians 1:30, 15:22, 2 Corinthians 5:17, 5:21, Galatians 2:20, 3:26-28, Ephesians 1:3-14, 2:6, 2:10, Philippians 3:9, Colossians 2:10, 3:3