Union with Christ
he Reformers are remembered for the cry sola fide, faith alone. Their opponents answered that such a doctrine would empty the churches of holiness: if a man is accepted by God apart from his works, why should he trouble to do any? The answer the Reformers gave was not a qualification of faith alone. It was a deeper account of what faith receives. Faith does not merely receive a verdict. It receives Christ Himself, and in Christ everything He is.
That is the doctrine of union with Christ, and it lies underneath nearly everything else the Reformation recovered. The New Testament’s favorite description of a Christian is not “a forgiven person” or even “a believer,” but someone who is in Christ. Every spiritual blessing is ours “in Christ” (Ephesians 1:3). “If anyone is in Christ, he is a new creation” (2 Corinthians 5:17). “I have been crucified with Christ. It is no longer I who live, but Christ who lives in me” (Galatians 2:20).
Nothing to Us Until We Are One with Him
John Calvin opens the third book of his Institutes, the book on how we receive the grace of Christ, with the doctrine of union. He does not begin with justification. He begins with the question that must be answered first: how do the benefits of Christ become ours at all? His answer is that so long as Christ remains outside of us and we are separated from Him, all that He suffered and did for the salvation of the human race remains “useless and of no value for us.” Christ must become ours and dwell within us. We are said to be grafted into Him and to put Him on, and all that He possesses is nothing to us until we grow into one body with Him.1
The bond of that union, Calvin continues, is the Holy Spirit, and the instrument on our side is faith. We are not joined to Christ by a feeling, a ceremony, or an ecclesiastical system, but by the Spirit working faith through the Word.
The Marriage of the Soul
Luther had found the same truth in the most intimate image Scripture offers. In The Freedom of a Christian (1520) he described faith as a wedding:
The third incomparable grace of faith is this, that it unites the soul to Christ, as the wife to the husband; by which mystery, as the Apostle teaches, Christ and the soul are made one flesh.2 Martin Luther
And in marriage, Luther reasoned, all that each partner has becomes the other’s. Here the exchange is wholly unequal. Christ is full of grace, life, and salvation; the soul is full of sin, death, and condemnation. “Let faith step in,” he wrote, “and then sin, death, and hell will belong to Christ, and grace, life, and salvation to the soul.” The rich and righteous Bridegroom takes a poor and sinful bride, and by “the wedding-ring of faith” makes her debts His own and His riches hers.3
Knit Together Inseparably
Tyndale taught the same doctrine to English readers. In the Pathway he wrote that by grace we are “plucked out of Adam, the ground of all evil, and graffed in Christ, the root of all goodness.” Christ’s blood, His death, all that He ever did is ours, “and Christ himself, with all that he is or can do, is ours.”4 In The Parable of the Wicked Mammon he pressed the union to its boldest conclusion:
Christ is thine, and all his deeds are thy deeds. Christ is in thee, and thou in him, knit together inseparably. Neither canst thou be damned, except Christ be damned with thee: neither can Christ be saved, except thou be saved with him.5 William Tyndale
That is assurance grounded not in the strength of the believer’s grip but in the reality of the bond. A Christian can no more be lost than Christ can.
The Double Grace
What then does union with Christ give? Calvin answered with a phrase that has become a landmark of Reformed theology. At the head of his chapter on justification he wrote that Christ was given to us to be grasped and possessed by faith, and that “by partaking of him, we principally receive a double grace.” The first is that, reconciled to God through Christ’s blamelessness, we have in heaven a gracious Father instead of a Judge. The second is that, sanctified by Christ’s Spirit, we cultivate blamelessness and purity of life.6
The duplex gratia, the double grace, is justification and sanctification. Both come from the same source, the one Christ. Both are received by the same means, union with Him through faith. Neither can be had without the other, because Christ cannot be divided. As Paul says, Christ Jesus “became to us wisdom from God, righteousness and sanctification and redemption” (1 Corinthians 1:30). Calvin drew the conclusion directly: Christ justifies no one whom He does not at the same time sanctify.7
Faith Alone, but Never Alone
This is how the Reformers answered Rome’s objection. In his Antidote to the sixth session of the Council of Trent, Calvin gave the classic formula:
It is therefore faith alone which justifies, and yet the faith which justifies is not alone: just as it is the heat alone of the sun which warms the earth, and yet in the sun it is not alone, because it is constantly conjoined with light.8 John Calvin
Faith alone is the instrument of justification. But the faith that justifies is never solitary in the person who has it, for it unites him to a living Christ who also sanctifies. The Westminster Confession, and the Second London Baptist Confession after it, put the same truth in confessional form: faith is the alone instrument of justification, “yet is it not alone in the person justified, but is ever accompanied with all other saving graces, and is no dead faith, but worketh by love.”9
Luther, for his part, had already shown where union leads. A Christian, he concluded at the end of The Freedom of a Christian, does not live in himself, but in Christ and in his neighbor: “in Christ by faith, in his neighbour by love.”10
What the Doctrine Does Not Mean
Union with Christ is among the richest doctrines of the Reformation, and for that reason among the most easily distorted. Four cautions are worth keeping.
It does not merge justification into sanctification. The Council of Trent defined justification as “not remission of sins merely, but also the sanctification and renewal of the inward man.”11 On that view, a sinner is accepted by God in proportion as God’s grace makes him righteous within. The Reformers’ doctrine of union says something different. Justification and sanctification are inseparable because both flow from Christ, but they are not the same gift. Justification is God’s verdict, complete and once for all, resting on Christ’s righteousness counted as ours. Sanctification is God’s renewal, real but growing and never complete in this life. Calvin’s image holds both truths together: the sun’s heat and light are never apart, yet heat is not light.
It does not blur the Creator and the creature. In Calvin’s own day the Lutheran theologian Andreas Osiander taught that we are justified by the indwelling of Christ’s essential divine righteousness. Calvin answered him at length in the Institutes (3.11.5–12). Union with Christ is real and spiritual, wrought by the Holy Spirit, but it does not dissolve the believer into God or make Christ’s divine nature the believer’s own. We are one with Christ as members with their Head, as a bride with her Husband, and never otherwise.
It does not set union against imputation. Some modern writers have suggested that if we are united to Christ, the doctrine of imputed righteousness becomes unnecessary. Calvin did not think so. He held both together: it is precisely because we are joined to Christ that His righteousness is reckoned to us as our own (Philippians 3:9; 2 Corinthians 5:21).12 Union is the setting of imputation, not its replacement.
It is not a mystical experience detached from the Word. Union with Christ is not a state reached by contemplation, nor a feeling that must be cultivated before one may count oneself a Christian. It is the work of the Spirit through the gospel, received by faith, and nourished by the Word, the sacraments, and prayer. The humblest believer who trusts Christ is as truly united to Him as the most advanced saint.
Why It Still Matters
The doctrine of union guards the gospel on both flanks. Against those who fear that free justification will breed indifference, it answers that no one receives Christ’s pardon without receiving Christ, and no one receives Christ without receiving His Spirit. Against those who would make holiness the ground of acceptance, it answers that our standing rests on Christ’s righteousness, not on our progress, and that our progress itself is His gift.
For the believer, it is the deepest comfort the Reformation offers. Your sins were laid on Him; His righteousness is laid on you. Your struggle toward holiness is not a lonely effort to earn a place you do not have, but the life of Christ working in one who already belongs to Him. And you are knit to Him so fast, as Tyndale said, that you cannot be lost unless He is lost with you.
“For you have died, and your life is hidden with Christ in God. When Christ who is your life appears, then you also will appear with him in glory” (Colossians 3:3–4).
Theological Recoveries Next: The Priesthood of All Believers
