For we are members of His body, of His flesh and of His bones.
Ephesians 5:30 NKJV
Question 66 of the Larger Catechism, asks, “What is that union which the elect have with Christ?” It gives the answer, “The union which the elect have with Christ is the work of God's grace, whereby they are spiritually and mystically, yet really and inseparably, joined to Christ as their head and husband; which is done in their effectual calling.” Last week we looked at the special benefits belonging to the invisible church. This week we consider what it means to be united to Jesus Christ.
As we saw in Question 65, the Catechism first mentions “Union with Christ” as a benefit belonging exclusively to the “invisible church.” However, when it defines what that union is here in our question, it speaks of it as a state enjoyed by the elect. And so we could ask, is there a difference between the elect and the invisible church, and if so, what is it? The answer is that there is a difference between God’s elect and the invisible church. The elect are that group of people chosen by God from all eternity who will definitely be saved by Him at some point in time. The invisible church are those elect people who have actually been brought into that state of salvation. Thus, a Christian should know and affirm that he was always a member of God’s elect, even while he was an unbeliever: “He chose us in Him before the foundation of the world,” (Eph. 1:4). Yet, at the same time, he should understand that he did not become a member of the invisible church until God actually regenerated him and gave him faith in Christ and repentance from his sins: “He delivered us from the domain of darkness, and transferred us to the kingdom of His beloved Son” (Col. 1:13).
Accordingly, union with Christ is a benefit which is only enjoyed by the invisible church. As our question states it, “The union which the elect have with Christ is the work of God’s grace… which is done in their effectual calling.” Until the elect sinner is called by God to faith and repentance he is not united to Christ. And so what is this union which we have with Christ? First, we see that it is a work of God’s grace. No one has ever experienced union with Christ by his own works, will, or efforts. Union with Christ is God’s work, and it is God’s work of grace. Remember grace is God’s unmerited – that is, undeserved and unearned – favor. If you have been made a recipient of God’s grace, God has done this not because of anything in you now, or foreseen by God to be in you in the future under the right conditions. God’s favor comes to you because of God, not because of you. And what this favor does is the greatest of all possible benefits: God, through His Son, unites you to Himself!
Let’s look at this union. The Scripture at the head of this article speaks of it in graphically physical terms, but that terminology is used to express the reality of the union. Our union with God cannot be physical, for God is not physical. So we should not understand our union as being or becoming a part of God somehow. It is a spiritual and mystical union. The word mystical means sacred and mysterious. We do not see or sense the union but we know it is true, for God says in many places in His Word, that in our salvation we are forever joined to Him (John 14:17-20; 15:5; Eph. 1:22; 3:17; 5:23). Furthermore, we know that this joining is accomplished by the Holy Spirit, who, in some sense, makes us “one spirit with Him,” (1 Cor. 6:17). Thus, we know, as the Catechism describes it, that we are “really and inseparably joined to Christ.” The union is real. It will never end. But it must remain somewhat of a mystery to us this side of heaven.