What is a Christian? Have you noticed how the Bible rarely uses the language we often do today? It seldom calls people “believers,” and the title “Christian” appears only a handful of times. New Testament writers address their readers as “brothers and sisters” or “saints,” but by far the most common description of a Christian is someone who is “in Christ.”
Take Ephesians 1 as an example. In the opening blessing (vv. 3–14), Paul erupts in praise to “the God and Father of our Lord Jesus Christ,” tracing all spiritual blessings from the Father, through the Son, and applied by the Spirit (v. 14). Notice where these blessings are located: “in Christ.” Read vv. 3–14 and mark every instance of “in him,” “in Christ,” “in whom,” or “in the Beloved.” (There are roughly 10–12 occurrences!) Here’s the start:
Ephesians 1:3–6 (ESV)
3 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, 4 even as he chose us in him before the foundation of the world, that we should be holy and blameless before him. In love 5 he predestined us for adoption to himself as sons through Jesus Christ, according to the purpose of his will, 6 to the praise of his glorious grace, with which he has blessed us in the Beloved.
Union with Christ is like the Christmas stocking that holds all the other gifts of grace. Through this vital, mystical union—brought about by God’s grace as we respond in faith—we are justified (Christ’s righteousness credited to us), sanctified (the Spirit conforming us to Christ’s image), and will one day inherit glory (what only the perfect Son deserves, yet we receive in him).
This completely transforms how we think about our identity. We often ask, “Who am I?” or “Whose am I?”—both biblical questions. But Scripture also presses us to ask, “Where am I?”
- Are you dead in trespasses and sins, or alive together with Christ? (Ephesians 2:1–10)
- Are you in the domain of darkness, or in the kingdom of the beloved Son? (Colossians 1:13)
- Are you among the wicked, or in the congregation of the righteous? (Psalm 1)
- Are you in Adam, or in Christ? (Romans 5)
- Are you in the flesh, or in the Spirit? (Romans 7–8)
Union and Communion
In John 15, Jesus declares himself the vine and his disciples the branches (vv. 1–16). He repeatedly uses “abide in me” language. In one sense, this describes our unbreakable union with him, rooted in his saving grace and finished work (vv. 9, 16; cf. John 6:37—”All that the Father gives me will come to me, and whoever comes to me I will never cast out”).
Yet Jesus also uses “abide in me” in exhortations: “If you abide in me…” (vv. 5–7). These are calls to ongoing dependence, obedience, and delight in him, for “apart from me you can do nothing.”
How can union be fixed while abiding seems conditional? Jesus explains his purpose:
John 15:11 (ESV)
These things I have spoken to you, that my joy may be in you, and that your joy may be full.
If you have faith in Jesus, your union with him is secure—God has accomplished it once for all. But your communion—the felt experience of closeness, joy, and fellowship—can be disrupted by sin, distraction, or neglect.
We often confuse the two when battling sin. Prolonged struggle can lead to despair: “Maybe I was never really a Christian.” Self-examination is biblical (2 Corinthians 13:5), but if you’re in Christ and earnestly fighting sin (whether winning battles or not), your union remains unchanged. What wavers is communion—the joy of felt fellowship.
Sin doesn’t sever your union; it clouds your communion. You’re still in Christ, but your attention is elsewhere—like being physically present with my children yet mentally absent until they call “Daddy!” three times. Or, more starkly, like being one with your spouse yet flirting with another.
Sin robs us of joy in communion. Union is the foundation (secure, objective); communion is the enjoyment (variable, subjective).
Comfort and Challenge
If you are in Christ, you already possess every spiritual blessing in the heavenly places by grace through faith.
So don’t settle for a joyless Christian life. How is your communion with Jesus right now?
- Do you enjoy prayer, or has it become a duty?
- Do you delight in God’s goodness, or merely acknowledge it?
- Do you receive God’s gifts as pathways to enjoying him more?
- Is your faith a living walk with the King, or a checklist to complete?
- What sin is currently disrupting your communion with the King?
- What distractions consume your time and thoughts, hindering rather than helping your abiding?
May the Lord draw you deeper into abiding, that his joy may be in you and your joy full.
If you want to read more on this, can I recommend 2 books in our library:
- One with my Lord, Sam Allberry
- Home with God, Kyle Worley
Grace to you, Glory to God.