The theme of union with Christ may be the one of the most under-emphasized doctrines today. I recently asked a group I was teaching to raise their hands if they have ever heard a sermon or talk on union with Christ. Nothing! Yet as I have been studying this theme recently, I am increasingly convinced of its vast scope and central importance.

What is Union with Christ?

For a general definition of union with Christ, I will draw from a few systematic theologians. Wayne Grudem defines union with Christ, “Union with Christ is a phrase used to summarize several different relationships between believers and Christ, through which Christians receive every benefit of salvation. These relationships include the fact that we are in Christ, Christ is in us, we are like Christ, and we are with Christ” (Systematic Theology, 840). Millard Erickson defines union with Christ, “In one sense, union with Christ is an inclusive term for the whole of salvation; the various other doctrines are simply subparts.” (Christian Theology, 877). Erickson chooses three major categories of union with Christ. One, a judicial sense as believers are in Christ from the legal perspective and gain his righteousness. Second, a spiritual sense as the Holy Spirit is in the believer (1 Cor 12:3; Rom 8:9-11), a union of two spirits, the person and Holy Spirit. Third, a vital sense as Christ’s life flows into the believer, renewing his or her nature and imparting strength (Rom 12:2; 2 Cor 4:16). Erickson states, “Union with Christ is a generally inclusive term for all of salvation. It is also specific, referring to an intimate relationship with Christ”(880-881).

Michael Horton in The Christian Faith defines union with Christ as, “a way of speaking about the way in which believers share in Christ in eternity (by election), in past history (by redemption), in the present (by effectual calling, justification, and sanctification), and in the future (by glorification)” (587). Horton defines the nature of union with Christ with three aspects. Union with Christ is 1) mystical (transcends earthly analogies, intimate in communion, and has great transforming power), 2) legal (justified in God’s sight and adopted into his family), and 3) organic (we live in him and he abides in us). According to Constantine Campbell, Michael Horton incorporates a definition of union with Christ that is broad and deep, “According to Horton, union with Christ brings together all the disparate elements of salvation: ‘past, present, and future, as well as the objective and subjective, historical, and existential, corporate and individual, forensic, and transformative’” (Paul and Union with Christ, 56). Campbell himself summarizes the idea of union in Christ according the Apostle Paul’s writing with four themes—union with Christ being the “metatheme” and the four aspects being subparts. “The term ‘union with Christ’ is deemed insufficient to convey all that Paul includes in the theme…To do justice to the full spectrum of Paul’s thought and language, the terms union, participation, identification, and incorporation are adopted” (29). Campbell summarizes the four aspects of the metatheme union with Christ; “Union gathers up faith union with Christ, mutual indwelling, Trinitarian, and nuptial notions. Participation conveys partaking in the events of Christ’s narrative. Identification refers to believers’ location in the realm of Christ and their allegiance to his lordship. Incorporation encapsulates the corporate dimensions of membership in Christ’s body. Together these four terms function as ‘umbrella’ concepts, covering the full spectrum of Pauline language, ideas, and themes that are bound up in the metatheme of ‘union with Christ’” (413).

Union and the Doctrine of Salvation

Robert Letham says, “Union with Christ is right at the center of the Christian doctrine of salvation. The whole of our relationship with God can be summed up in such terms” (Union with Christ, 1). Letham goes on to state,

Union with Christ is crucial to, and at the heart of, the biblical teaching about salvation.

The Bible mentions union with Christ hundreds of times. The theme is mentioned in Paul’s letters over two hundred times and more than two dozen times in the writings of John. Letham lists some of the most important passages on union with Christ as Eph 1:3-14; John 14:16-ff; John 17:21-ff; 1 Peter 1:3-4; Rom 5:12-21 (as it relates to justification); Rom 6:1-4ff (as it relates to sanctification); and 1 Cor 15:12-ff (as it relates to resurrection).

Here is a sampling of passages related to aspects of union.

• Our identity is found in Christ (Phil 3:9)
• We are kept secure in Christ (Rom 8:39)
• We are saved in Christ (2 Tim 1:9)
• We are made clean and forgiven in Christ (1 Cor 1:30)
• We follow God’s ways in Christ (Col 2:6)
• We labor for God in Christ (1 Cor 15:58)
• We obey in Christ (Eph 6:1)
• We die to sin and are resurrected in Christ (Rom 6:5-11)
• We conquer in Christ (Rev 14:13)

Also, notice these four images that describe aspects of union with Christ:

1. Marriage – we are connected to Christ in a covenant of love (Eph 5:22-23)
2. Body—we are joined together as a family, joined to Christ as Head (Eph 4:15-16)
3. Building—we are a temple of God where Spirit lives, Christ the cornerstone (Eph 2:19-22; 1 Pet 2:4-5)
4. Vine and Branches—we are connected to Jesus, the vine, for spiritual vitality and strength (John 15:1-17)

Thus, the union with Christ is a theme with a vast scope, encompassing many aspects of our salvation.  Kevin DeYoung describes it this way: “The whole or our salvation can be summed up with reference to this reality. Union with Christ is not a single specific blessing we receive in our salvation. Rather it is the best phrase to describe all of the blessings of salvation, whether in eternity past (election), in history (redemption), in the present (effectual calling, justification, and sanctification), or in the future (glorification)” (Hole in our Holiness, 94). Wayne Grudem also explains the wide-sweeping nature of the theme of union with Christ in relation to the aspects of salvation. He explains, “Every aspect of God’s relationship to believers is in some way connected to our relationship with Christ. From God’s counsels in eternity past before the world was created, to our fellowship with God in heaven in eternity future, and including every aspect of our relationship with God in this life—all has occurred in union with Christ… In fact, every stage of the application of redemption is given to us because we are “in Christ.” It is “in Christ” that we are called to salvation (1 Cor. 7:22), regenerated (Eph. 1:3; 2:10), and justified (Rom. 8:1; 2 Cor. 5:21; Gal. 2:17; Eph. 1:7; Phil. 3:9; Col. 1:14). “In Christ” we die (1 Thess. 4:16; Rev. 14:13) and “in him” our bodies will be raised up again (1 Cor. 15:22)” (840, 843).

Kenneth Keathley in his chapter “Doctrine of Salvation,” in Theology for the Church, strongly emphasizes the centrality of union with Christ by explaining that the aspects of salvation all exist under the umbrella of union. “Union with Christ is not one phase or aspect of salvation; it is the whole of salvation in which all other aspects are subsets.” Keathley explains, “The Bible emphasizes several aspect of salvation—justification, sanctification, and adoption, among others—but they all fit under the general heading of ‘union with Christ.’” (John 15:5; 2 Cor 5:17; Gal 2:20) (543). Keathley says, “The Bible proclaims that Jesus Christ is salvation, and all who have a relationship with him (i.e. are united with him by faith) are saved. Union with Christ is the core truth of salvation that can be seen either as encompassing all of salvation or as the center to which all components of salvation are connected. Scripture presents the components of salvation from four different perspectives: eternal, historical, present, and eschatological” (544). Keathley also cites John Murray as a major proponent for the view that union with Christ is a major doctrine. John Murray said that, “Union with Christ is really the central truth of the whole doctrine of salvation…Indeed the whole process of salvation has its origin in one phase of union with Christ” (Redemption Accomplished and Applied, 161). Keathley summarizes, “Our union with Christ in his life, death, and resurrection provides the basis for our justification, sanctification, and glorification” (545).

To Summarize

I noticed many authors point out various perspectives of union within the storyline of Scripture.

1. Eternity Past: we are chosen for salvation in Christ (election) (Eph 1:4; 2 Tim 1:9).
2. Historical: Christ’s sacrifice on the cross for our sins (atonement)—result is that we are united to Christ in his life, death, and resurrection (Eph 1:6-7; Col 3:3-4; Rom 6:2-8).
3. Conversion (beginnings): Conversion elements are in Christ (regeneration, repentance/faith, justification, adoption) (Eph 2:8-10).
4. Present and Future: Christian Growth is in Christ—by and through his power and strength and all future benefits of salvation are given to those united with Christ (glorification) (Eph 2:8-10; 1 Thes 4:14-18; 1 Cor 15:22).

Salvation is like a diamond. It has many facets and sides that each sparkle with great beauty as they are studied. The theme of union with Christ is a doctrine that is most like the whole diamond of salvation, putting in context the many facets of salvation. I have merely scratched the surface of this theme, but it has become clear that the idea of union with Christ is vast in its scope and truly awe inspiring in its depth and breadth!