Sanctification and Union with Christ
The Christian world is thinking and talking a lot about sanctification; how to grow in godliness and live holy lives. Amen! O that we would do so more and more! But I want to contend that in thinking through a believer’s sanctification we cannot do so rightly without first thinking through our union in Christ.
The whole warp and whoof of Paul’s theology (including his theology of sanctification) is grounded in his understanding of who he is (and thus, who we are) in Christ. It is his doctrine of union in Christ that pulsates like a great melodic line running through the entirety of Paul’s thought. He’s a theologian of the preposition using phrases like “in Christ” “with Christ” or “through Christ” hundreds of times in his writing. And this makes sense considering how Paul came to faith. While out persecuting Christians, Paul is confronted by the resurrected Jesus and Christ’s first question to him was, “Saul, Saul, why are you persecuting me?” Not Christians, but me!
That question must have struck him as incredibly significant because it took Saul another three years of focused study (Gal. 1:7) to more fully figure out that Jesus Christ was in fact one with those who believed in him as the Messiah. When Saul was out imprisoning Christians, he was imprisoning, as it were, those who were in union with Christ. He was persecuting Jesus. But how could that be?
The answer, wrapped up in Jesus’ revealing of the Trinity, is the Christ-centered work of the Spirit of God, the Spirit of Christ himself indwelling believers. And it’s in the Spirit’s indwelling where he brings believers to spiritually unite with Christ and thus become partakers of all that is in Christ. By the Spirit Christ is in us (Eph. 3:16-17) and we are in Him (Eph. 2:10). But the million-dollar question is this: Why do we need to be found in Christ? Or better yet, what exactly is in Christ that demands my being united with him? As it turns out, quite a lot!
Wisdom, righteousness, sanctification, and redemption (1 Cor. 1:30). Every spiritual and heavenly blessing (Eph. 1:3). Grace (2 Tim. 2:1). The immeasurable riches of his grace in kindness (Eph. 2:7). God’s Fatherly love (Rom. 8:39). Humility (Phil 2:5-7). Suffering and comfort (2 cor. 1:5). Illuminated understanding (2 Cor. 3:14). Freedom (Rom. 8:2). Peace (Eph. 2:14). Inheritance (Rom. 8:17). Eternal life (Rom. 6:23). Salvation (2 Tim. 2:10). And this is just scratching the surface!
As John Calvin so memorably put it, “we must understand that as long as Christ remains outside of us, and we are separated from Him, all that He has suffered and done for the salvation of the human race remains useless and of no value for us… For, as I have said, all that He possesses is nothing to us until we grow into one body with Him. It is true that we obtain this by faith.”
And it’s precisely here, in a believer’s union with Christ, where our sanctification – our growth in godliness – really finds impetus. First, we see that there is a definitive and positional sanctification for those found in Christ. As believers united to Christ there is something definitively new in our relationship to sin, the world, and Satan that was not true of us before. In Christ we are positionally set apart. This is Paul’s whole argument in Romans 6:
“What shall we say then? Are we to continue in sin that grace may abound? By no means! How can we who died to sin still live in it? Do you not know that all of us who have been baptized into Christ Jesus were baptized into his death? We were buried therefore with him by baptism into death, in order that, just as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life.”
From this positional sanctification – our being baptized into Christ – we are brought to participate in the power by which we grow in Christlikeness. As Paul argues in Ephesians 2, it is “by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast. For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them” (Eph. 2:8-10).
Do you see? Our union in Christ, what Paul refers to here as being created in Christ Jesus, is what leads to good works; works that we will walk in! Ultimately this helps remind us that our sanctification – our growth in godliness – is not first a matter of effort or trying hard but preeminently a matter of faith. It is in Christ where our obedience is found and the Spirit of Christ where that obedience, which God prepared beforehand, is worked out in our lives.
So here’s the two-million dollar question: Are you looking to yourself to grow in holiness or are you looking and trusting and believing in Christ? Perhaps Paul said it better: “Did you receive the Spirit by works of the law or by hearing with faith? Are you so foolish? Having begun by the Spirit, are you now being perfected by the flesh” (Gal. 3:2-3). Oh, that our sanctification would be grounded in our Savior, Jesus Christ. “You are in Christ Jesus, who became to us wisdom from God, righteousness and sanctification and redemption, so that, as it is written, “Let the one who boasts, boast in the Lord” (1 Cor. 1:30-31).
Stephen Unthank (MDiv, Capital Bible Seminary) serves at Greenbelt Baptist Church in Greenbelt, MD, just outside of Washington, DC. He lives in Maryland with his wife, Maricel and their two children, Ambrose and Lilou.
 John Calvin, Institutes of the Christian Religion, John T. McNeill, ed, Ford Lewis Battles, trans, Library of Christian Classics (Philadelphia: Westminster, 1960 ), III.i.1.
 Also, if you’ve never done so, you should read and reread John Murray’s fantastic chapters on Definitive Sanctification and Progressive Sanctification found in his collected works. They will lead you deeper into this study than can be given in a short blog post. John Murray, Collected Writings of John Murray, Volume 2: Systematic Theology (The Banner of Truth Trust, 2001), pp. 277-317.
 As John Murray puts it, “our death to sin and newness of life are effected in our identification with Christ in his death and resurrection, and no virtue accruing from the death and resurrection of Christ affects any phase of salvation more directly than the breach with sin and newness of life. John Murray, Collected Writings of John Murray, Volume 2: Systematic Theology (The Banner of Truth Trust, 2001), pp. 287.