I’ve made some broad statements about union and Paul’s emphasis of it and the centrality of it in Paul’s addressing of the problem of sin. But what is the nature of this union? How do we talk about union with Christ?
NATURE OF THE UNION
There are many pictures given of this union and what it is like. Paul employs two images in Ephesians 5. Paul calls Christians “Members of one body,” (Ephesians 4, 5:30) namely Christ’s body. Paul also interweaves that analogy with one of marriage, speaking of how the Church is Christ’s Bride and quotes Genesis about how “the two became one” picturing how Christ is united to His church. John uses organic imagery such as a vine and branches in John 15. Life flows from the vine to the branches, picturing the vital connection of believers to Christ.
The most mysterious imagery used, however, must be said to be John’s imagery in John 17. There, John records the words of Christ:
John 17:21 that they may all be one, just as you, Father, are in me, and I in you, that they also may be in us, so that the world may believe that you have sent me.
Here, John links the union of Father and Son and union with Christians. Union with Christ is seen to also be union with the Father. But also, the closeness of the Father to the Son is used as a goal for the completeness and nearness of union desired with believers.
The mysterious part of John’s image is the realization that such a reflection without qualification can lead to an idea that is counted heretical. We cannot understand Jesus to mean that believers are united in essence with the Father as Jesus is, becoming God as Christ is. However, Eastern Orthodoxy has spoken about the concept of “deification” as the final element of salvation. Reformed Christians have as their final element “glorification” meaning much of what Eastern Orthodox mean by “deification,” namely not that we become by nature God, but that we come all that Christ was in his human nature in his glorified state. Such a state, we must understand, means a nearness and abilities of perception, enjoyment of God and even becoming “partakers of the divine nature” as Peter says. The Greek word “partaking” there means partnering, companion, or communing fellow. Not becoming God, but communing on the most intimate level with God, in like manner as God the Father and God the Son commune with each other. A request at this point for more precision in definition will leave us wanting. Peter’s words are perhaps the highest thoughts and manner of putting such a reality as we are able to grasp this side of the experience.
Thus we see, the task of grasping union’s nature may be slippery due to 2 factors:
1. Union is spiritual. Paul tells us that in union, we are “made to drink of one spirit” (1 Cor 12:13). Then, in Ephesians 1 Paul tells us we are united to Christ, by being sealed by the Spirit. The Spirit is the means of union. The Holy Spirit ties one to Christ and applies the benefits of that union, thereby binding all partakers together in one body. Such a truth leads us to declare:
2. Union is Mystical, or a mystery. As Paul explores this idea of being bound together into Christ’s body he writes:
Eph 5:30 because we are members of his body.
Eph 5:31 "Therefore a man shall leave his father and mother and hold fast to his wife, and the two shall become one flesh."
Eph 5:32 This mystery is profound, and I am saying that it refers to Christ and the church.
This doctrine is mystical. It is even called that by John Calvin: “The Mystical Union.” It is frustrating preparing a lesson for, because you ask certain questions of it and you get back Paul’s answer: “This mystery is profound.” We are rationally minded, especially as Reformed believers, but here is a mystery beyond our reason. The exact nature of this union is beyond our comprehension, so all we are left with is the awe of it. Our questions on the exact nature then are passed by to ask what are the benefits of union.
HOW BLESSINGS ARE BESTOWED
When looking to the work of Christ in regards to salvation, our main concern tends to be Christ’s death. Christ died for sins, and we may call this Passive Obedience, or suffering the penalty of sin. This is what Paul was speaking of in Romans 5:10 when we learn that we are “reconciled to God by the death of his Son.” In Christ’s death, we share in this reconciliation. Yet, this is not all that Christ did. Christ declares:
Matt 5:17 "Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them.”
Christ also gains the rewards of the law merited by his obedience. We call this Active Obedience. All that might be gained by obedience to the Law is gained for believers through Christ.
In explaining how this relationship works, Reformation Christians have either refered to this as a Law and Gospel Hermeneutic (Lutherans) or in terms of a Covenant of works and a Covenant of grace. The Law or the covenant of works is given to Adam and humanity, that “if you do this, you will live.” Adam violates the covenant and the rest of humanity, marred by sin, are unwilling and unable to fulfill the covenant of works. In Paul’s language, it takes a second Adam, a new man to fulfill the Law. That man is Christ. By virtue of Christ’s obedience to the covenant of works, a covenant of Grace is given. We first see this in Gensis 3:15, a promise of a seed that will defeat sin and restore humanity to fellowship with God. On this basis is the covenant of grace given, one based on Christ’s fulfillment of the covenant of works. The rewards of Christ's fulfilling the law by works are given merely to be received by faith. Whereas the covenant of works was “obey and you will live,” (Genesis 2:16-17) the covenant of grace is “believe and you will be justified.” (Genesis 15:6)
THE BENEFITS GAINED BY CHRIST
Looking at Questions 30-36 in the Smaller Catechism, we now may see something we hadn’t noticed before:
Question 30. How does the Spirit apply to us the redemption purchased Christ?
Answer. The Spirit applies to us the redemption purchased by Christ, by working faith in us, and thereby uniting us to Christ in our effectual calling.
What then is applied in uniting us to Christ’s work?:
Question 32. What benefits do they that are effectually called partake of in this life?
Answer. They that are effectually called do in this life partake of justification, adoption, sanctification, and the several benefits which, in this life, do either accompany or flow from them.
Though we will name more, the important three named are justification, adoption and sanctification.
Reformed Christians tend to express the benefits of salvation in the Order of Salvation (the Ordo Solutis). Unnamed in the ordo solutes is union. This is because union is not a step in the process, but the foundation from which all other benefits flow. Looking at a few of the elements we can see our regeneration being Christ’s regeneration:
regeneration, (resurrection applied to soul)
(1Co 15:21-22 For as by a man came death, by a man has come also the resurrection of the dead. For as in Adam all die, so also in Christ shall all be made alive.)We also see our justification by grace through faith being on the basis of Christ’s justification by merit through works:
Rom 4:25 - [Christ] was delivered up for our trespasses, and was raised for our justification.Christ's resurrection, then, can be seen as his justification, the basis of our justification bestowed to us.
Php 2:8-9 And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross.
Php 2:9 Therefore God has highly exalted him and bestowed on him the name that is above every name,
Our sanctification is on the basis of Christ’s sanctified work:
1Co 1:2 To the church of God that is in Corinth, to those sanctified in Christ Jesus, called to be saints together with all those who in every place call upon the name of our Lord Jesus Christ, both their Lord and ours:Our adoption is because we are united to the Son:
Eph 1:5 he predestined us for adoption as sons through Jesus Christ, according to the purpose of his will
And our glorification awaits as Christ’s has been gained:
Rom 8:17 and if children, then heirs--heirs of God and fellow heirs with Christ, provided we suffer with him in order that we may also be glorified with him.
Such an understanding of salvation based on Christ’s passive and active obedience gives us a larger, broader picture of the accomplishment of Christ. We are not merely saved “by His death” as great and wonderful news as atonement and reconciliation is to our war-beaten souls. We are also “saved by His life.” We are saved on the basis of Christ’s fulfillment of the law in our place, applied to us by the Holy Spirit in union with us, as Christ’s life is communicated to those in covenant with God.
J. Gresham Machen, a founder of the Orthodox Presbyterian Church and Westminster Theological Seminary, was near death in the Midwest. In his last communication to John Murray, Machen communicated what doctrine gave him comfort at such a time:
“I'm so thankful for the active obedience of Christ. No hope without it."