Theology & Doctrine · FaithLogic

Union with Christ and the Christian Life

The New Testament's most frequent way of describing a saved person is 'in Christ'. Every benefit of salvation — regeneration, justification, adoption, sanctification, perseverance, glorification — is received by being joined to Jesus by the Spirit through faith. Sanctification, the actual making-holy that follows, is both a decisive break with sin's rule and a lifelong transformation; traditions differ on how it advances and whether the truly saved can finally fall away.

In brief

Union with Christ is the organising category of applied salvation (Calvin: we receive nothing from Christ 'until we grow into one body with him'). The New Testament expresses it with: the 'in Christ / in him / in the Lord' formula (Romans 8:1; 2 Corinthians 5:17; Ephesians 1:3–14); the body–head image (1 Corinthians 12; Ephesians 4:15–16); the vine and branches (John 15:1–8); the temple (Ephesians 2:21–22); marriage (Ephesians 5:31–32); 'Christ in you' and 'you in Christ' together (John 17:21–23; Colossians 1:27); and the 'with Christ' language of dying, being buried, raised, and seated (Romans 6:3–11; Colossians 2:12–13; 3:1–4; Ephesians 2:5–6).

The benefits flow from the union. Reformed theology speaks of the ordo salutis — regeneration → faith and repentance → justification → adoption → sanctification → perseverance → glorification — but these are not a conveyor belt so much as facets of the one union: united to Christ, you have his righteousness (justification), his sonship (adoption), his life (regeneration and sanctification), and his future (glorification).

Sanctification — the two aspects:

• Definitive (positional) sanctification — a decisive, past event: 'you were washed, you were sanctified' (1 Corinthians 6:11); believers are already 'saints' (hagioi, 'holy ones') and have 'died to sin' so that it no longer reigns (Romans 6:2, 6–14).
• Progressive sanctification — an ongoing work: 'being transformed into the same image from one degree of glory to another' (2 Corinthians 3:18); 'work out your own salvation … for it is God who works in you' (Philippians 2:12–13); the 'put off / put on' of Ephesians 4:22–24 and Colossians 3:5–14.

How progressive sanctification advances — the traditions:

• Reformed: growth in holiness through 'mortification' (putting sin to death, Romans 8:13) and 'vivification' (coming alive to righteousness), by the Spirit, using the ordinary means of grace (word, sacraments, prayer, fellowship); a lifelong fight never completed in this life (the 'already/not yet'; Romans 7 read by most as the ongoing Christian struggle).
• Wesleyan / holiness: a further work of grace ('entire sanctification' / Christian perfection) is available in this life, in which the believer is filled with perfect love and freed from the reigning power and the willful practice of known sin (not from mistakes, infirmities, or the possibility of falling).
• Catholic: sanctification (an increase of the sanctifying grace given in baptism) advances through the sacraments, cooperation with grace, growth in the virtues, and — a distinctive — is completed for most after death through purgation (purgatory) before the beatific vision.
• Keswick / 'higher life': victory over conscious sin comes not by struggle but by 'letting go and letting God' — surrender and faith; criticised by the Reformed for underplaying the fight.
• Eastern Orthodox: the whole Christian life is theosis — being progressively transformed by grace into the likeness of God, participating in the divine energies, a synergy of the Spirit and the person's ascetic effort.

Perseverance — can a true believer finally fall away?

• Reformed (perseverance / preservation of the saints): those God has effectually called and justified he will keep, and they will persevere in faith to the end (John 10:28–29; Romans 8:29–39; Philippians 1:6; 1 Peter 1:5). Warnings and apostasy passages are real means God uses to keep his people, and those who fall away finally 'were not of us' (1 John 2:19).
• Arminian / Wesleyan: genuine believers can, by persistent unbelief or willful sin, forfeit salvation (Hebrews 6:4–6; 10:26–29; the branches cut off, John 15; 'you have fallen away from grace', Galatians 5:4). Assurance is real but conditional on continuing in faith.
• Catholic: the justified can lose grace through mortal sin and be restored through penance; final perseverance is a special gift not infallibly promised to any individual.

Synthesis

FAITHLOGIC ANALYSIS. Ask the New Testament what a Christian is and the answer, 165 times over, is 'in Christ'. Salvation is not a set of separate gifts posted to you; it is one gift — Jesus himself — and everything else (a clean record, a new heart, adoption, holiness, a future body) comes with him, in him. Calvin's summary holds: we get nothing from Christ until we are joined to him.

Out of that union comes the Christian life. Its grammar is fixed: God first tells you who you now are — dead to sin, raised with Christ, a saint — and then commands you to live it out. Sanctification is real progress toward that reality, worked by the Spirit through your active effort ('you put to death … by the Spirit'), using ordinary means. Where the traditions divide is on the ceiling and the floor. Can it be finished here? The Wesleyan says a real 'entire sanctification' of perfect love is available; the Reformed, Catholic, and Orthodox say the fight lasts until glory (though the East frames the goal as theosis, ever-deepening participation in God). Can a true believer finally fall? The Reformed say God keeps his own and the warnings are how he does it; the Arminian says the warnings mean what they say. On the thing that matters most, all agree: you become holy not by climbing up to a God who will then love you, but by being joined to the Christ who already has.

Part of the FaithLogic Theology & Doctrine library. Open the full study for the original languages, the early witnesses, the councils, and the arguments.