Union with Christ sums up per­fectly what it means to be saved. In biblical teaching it looks back into eternity when we were cho­sen in Christ (Eph. 1:4); it includes the his­torical work of Christ when we died and rose with him (Rom. 6:5); it becomes an actual reality when we believe in Christ and are sealed with the Holy Spirit (Eph. 1:13); it inspires and empowers us for daily obe­dience and works of love (Rom. 7:4); it safeguards us when we come to die (1 Thess. 4:14); and it will ensure that we will be glorified with Christ when he returns (Rom. 8:17).

Truly, 

union with Christ is a very inclu­sive subject. It embraces the wide span of salvation ... it underlies every aspect of redemption both in its accomplishment and its application. Union with Christ binds all together. John Murray

The New Testament uses a number of pictures to help us imagine what this union is really like. It is more than a bond of com­mon interest, as in a social club. It is a bond of being and life that makes us one Spirit with the Lord (1 Cor. 6:17). It is like the solid oneness between the stones and the foundations of a building (Eph. 2:19-22), the neural communications between the brain and the parts of the body (Eph. 4:15­, 16), and the organic union between the stem and the branches of a plant (John 15:1-8).

More personally, it is like the intimate, lifelong union between husband and wife (Eph. 5:22-23). Most wonderfully of all, it is like the personal relations between the Father, Son and Holy Spirit (John 17:21­ 23). There is an outward and an inward side to union with Christ. Outwardly, union with Christ dates from his uniting himself with us in his miraculous human conception. Through his being born into the world he became our human represen­tative in the same way that the first Adam had been (Rom. 5:12-21).

Because Christ lived a wholly obedient human life that ended with the cross (Phil 2:5-8), he has, through his resurrection, ascension, enthronement and the outpour­ing of the Holy Spirit, brought a new cre­ation order into being, to which we now belong as those who are in Christ (2 Cor. 5:17). Inwardly, one writer likens union with Christ to an umbilical cord that ties us to Christ. But the inward union is more than a lifeline, it is Christ himself dwelling in and with us, through and in the Person of the Holy Spirit (Rom. 8:9f). The indwelling Spirit is so closely connected now with the exalted Christ that Paul can virtually identify the two (2 Cor. 3:17). Having the Holy Spirit, which all Christians do, means having the living Christ for our permanent guest.

What difference does and should union with Christ make in everyday living?

First, union with Christ makes the Christian life possible. Christian living is meant to be patterned on Christ’s own human life, a hopeless task for us in our own strength. Only Christ can make us Christlike, and he does this by coming in person to live in us and by empowering us from the inside out (Gal. 2:20).

Second, union with Christ is the basis of communion with the separate persons of the Godhead. The goal of salvation is knowing God and living our lives in fellow­ship with him. Union with Christ brings equal access to the Father and the Holy Spirit. It is the beginning of a growing friendship of love and closeness between us and the Triune God (John 14:23).

Third, union with Christ is the answer to sin’s control. We have been united with Christ at every stage of his redemptive accomplishment. This includes his dying to the controlling power of sin in human nature, and his rising again to a new kind of human life, centred on God and set free for doing God’s will. Uniting us with Christ is God’s method of grace, so that sin will no longer dominate us (Rom. 6:1­-14).

To the degree that the Christian ... takes seriously the reality of his Spirit-wrought union with Christ, to that degree he will find his definitive sanctification coming to actual expression in his experi­ential or progressive sanctification. The holiness of the Christian’s daily walk directly depends upon his union with the Saviour.Robert Reymond

Fourth, union with Christ is the way out of physical sins. Our bodies belong to Christ now by right of redemptive pur­chase. They are the temples of the Holy Spirit, the sphere for glorifying God in this life. There is no need nor excuse for us prostituting our bodies in sinful ways (1 Cor. 6:12-20).

Fifth, union with Christ brings sweet fellowship in suffering. When we suffer we do not suffer alone because Christ is with us and makes our sufferings his own. Our righteous sufferings become the occasion for knowing Christ better, and experienc­ing more of the power of his resurrection (Phil. 3:10).

Sixth, union with Christ binds all of us together. Being united to Christ means that we are united to one another as his church Body. This is our greatest resource for answering racism, feminism, and classism that create such divisions, even among Christians. It is also the answer to personal rivalries and animosities between Christians. Christ is all and in us all (Col 3:11).

Union with Christ is the bond of the covenant between us and God. It reminds us that every spiritual blessing comes to us in Christ (Eph. 1:3). “There is no more vital, sublime and glorious doctrine than this” (Martyn Lloyd-Jones).