Deep study
Paul's deepest theme - everything we have, we have 'in Christ'
To be a Christian is not merely to believe facts about Jesus but to be joined to Him, so that what is His becomes ours.
More than 160 times Paul says believers are in Christ or in him. It is his shorthand for the whole of salvation. In Christ we were chosen before the foundation of the world (Ephesians 1:4), redeemed and forgiven (Ephesians 1:7), made alive and seated in the heavenly places (Ephesians 2:5-6). We are not merely forgiven by a distant God; we are united to His Son, so that what is true of Jesus becomes true of us.
In the ancient world a king or head represented his people: what he did, they did with him. Paul uses exactly that logic. As everyone in Adam shares his fall, everyone in Christ shares His victory (1 Corinthians 15:22; Romans 5:12-19). This is why the gospel is good news outside of us first: our standing rests not on our performance but on our Head's. His obedience is credited to all who are joined to Him.
Paul stacks up with-words: we were crucified with Christ (Galatians 2:20), buried with him and raised with him (Romans 6:4-5), made alive together and seated together with him (Ephesians 2:5-6). His death to sin becomes ours; His resurrection life becomes ours. So Paul can say your life is hidden with Christ in God (Colossians 3:3) - your truest self is kept safe in Him.
Jesus pictured the same truth: I am the vine; you are the branches (John 15:5). A branch has no life of its own; it bears fruit only by remaining joined to the vine. Union is not a one-time transaction to file away but a living dependence - abide in me, and I in you. Apart from Him we can do nothing; in Him we bear much fruit.
Because we are in Christ, we are brought into the family in Christ. God predestined us for adoption as sons through Jesus Christ (Ephesians 1:5), and because we are sons, God sent the Spirit of his Son into our hearts, crying, Abba, Father (Galatians 4:6). We do not merely stand pardoned at a distance; we are given the Son's own status. And the inheritance follows: if children, then heirs - heirs of God and fellow heirs with Christ (Romans 8:17). Everything that belongs to the Son, the Father freely shares with those joined to Him.
Scripture's most intimate picture of union is marriage. Quoting the one-flesh union of Genesis 2:24, Paul writes, this mystery is profound, and I am saying that it refers to Christ and the church (Ephesians 5:31-32). Christ loved the church and gave himself up for her, to present her to himself in splendor (Ephesians 5:25-27). Believers are betrothed now - I betrothed you to one husband, to present you as a pure virgin to Christ (2 Corinthians 11:2) - and the wedding comes at the end (Revelation 19:7). Union with Christ is not a business partnership but a covenant one-ness, the joining of bridegroom and bride.
The benefits of salvation are not separate parcels handed out one by one; they are all found in one place - in Christ. Paul says God made Him to be our wisdom, our righteousness and sanctification and redemption (1 Corinthians 1:30); in him the whole fullness of deity dwells bodily, and you have been filled in him (Colossians 2:9-10). As the Reformers put it, as long as Christ remains outside of us, all He has done for us is of no value; the Spirit unites us to Him, and from that union every grace flows. This is why sanctification is simply becoming what you already are: since you have died and been raised with Christ, set your mind on things above (Colossians 3:1-3).
Union begins now and is consummated forever. Christ in you, the hope of glory (Colossians 1:27) becomes, at the end, the marriage of the Lamb: the church is His bride, made ready, and a voice cries, the marriage of the Lamb has come (Revelation 19:7-9). The deepest promise of all is face-to-face nearness: they will see his face, and his name will be on their foreheads (Revelation 22:4). The union sealed by the Spirit now is the union enjoyed in full when we are forever with the Lord (1 Thessalonians 4:17).