Union with Christ

The unio mystica sive praesentia gratiae tantum, the ‘mystical union’ or ‘union by the presence of grace alone’ refers to the special union ‘founded on the indwelling grace of God in Christ, that occurs between God and the believer in and through regeneration’ (Muller). It is a consistent feature of orthodox Reformed and Lutheran theological dogmatics. Remarkably given its prominence in the New Testament, it hadn't been the stimulus for much theological reflection prior to this - perhaps because sacramental theology was doing the 'work' that it now does in Protestant thinking.

The term ‘mystical’ is used because it rests on the mystery of grace and the mercy of God. It is also referred to as the unio spiritualis because this union is of the Spirit. The believer’s ingrafting into Christ constitutes the foundation of the Christian life. A number of New Testament metaphors are picked up in this teaching (vine,/branches, body/head) and also the en Christo terminology which appears so often. The believer’s individuality is not dissolved or thwarted in this union. Rather, it is the work of the Holy Spirit which produces faith and enables the believers to share in the blessings of the work of Christ.

John Murray observed that "Union with Christ is a very inclusive subject. It embraces the wide span of salvation from the ultimate source in the eternal election of God to its final fruition in the glorification of the elect." If we may observe one thing about how the doctrine has been treated in the Reformed tradition it might be that this very inclusivity and breadth makes it difficult to locate in the dogmatic system. It operates rather as the connective tissue between various doctrinal topics - as a motif rather than as a doctrine itself. Furthermore, the language of ‘union’ with Christ has led inevitably to some misconstruals.

IN CALVIN
Calvin scholars like Alister McGrath and Charles Partee have latterly recognised how pervasive and comprehensive Calvin’s doctrine of the unio mystica is. According to McGrath, Calvin utilises the concept of the distinctio sed non separatio drawn from Chalcedonian Christology. That is: the separateness yet distinction of the two natures in the hypostatic union is, for Calvin, the pattern for divine-human relationship found also in the unio mystica. Though the doctrine relates to the doctrines of justification and sanctification and how the believer receives these benefits of Christ’s death, the doctrine is also profoundly Trinitarian.

The basis for our union with Christ is the electing will of God the Father who chooses us ‘in Christ’ before the foundation of the world. Our union with Christ is an expression of the love and mercy of God himself (Inst II xvi.4); and in union with Christ we are brought into relationship with God through the Spirit of adoption, thereby experiencing the paternal love of God the Father. Calvin will refer to Christ himself as ‘the bond of our union with God’.

Calvin writes:
By partaking of him, we principally receive a double grace: namely that being reconciled to God through Christ’s blamelessness, we may have in heaven instead of a Judge a gracious Father; and secondly, that sanctified by Christ’s Spirit we may cultivate blamelessness and purity of life. (Inst III.11.1)

Union with Christ thus has a twin focus for Calvin. From union with Christ flow both justification – which occurs externally to the believer – and sanctification – which occurs internally. Not only is the forensic imputation of righteousness accomplished through union with Christ, but the life of Christ is also imparted to the believer as the basis for his or her sanctification. Both justification and sanctification are, as Evans writes, ‘subsumed under a more comprehensive reality – union with Christ.’ It is possible even to go so far as to conclude that the notion of unio Christi has for Calvin a causal priority in his soteriological thought. Justification is not dependent on sanctification, nor is it a response to justification.

In what does the union with Christ consist? Calvin holds that believers are united with the incarnate humanity of Christ. Christ’s mediatorial work and the benefits that flow from it – including, for Calvin, the imputation of Christ’s righteousness - are received by union with the substantia of the humanity of Christ. This notion pervades his teaching on the sacraments as a (in some way) real appropriation of Christ by the believer. ‘Calvin’s doctrine of union with Christ, as expounded in Book III and IV of the Institution and clarified in the context of Eucharistic debates, affirms nothing less than the reception by the believer of the substance, the very being, of the incarnate Christ. This union is the impartation of the life of the risen Christ to the believer, albeit in a manner which does not diminish the personal individuality of both Christ and the individual believer’ (William B. Evans, Imputation and Impartation – Union with Christ in American Reformed Theology, Milton Keynes: Paternoster, 2008 p.28). Justification involves not simply a forensic, past act of God through Christ in the past – it also involves communion with the person of the living Christ. It is likely that Calvin intended this notion of substantial union to indicate an ontological reality. Evans complains that this notion is underexplained by Calvin, which leaves open the possibilities of revision or rejection in subsequent generations.

Intriguingly, Calvin places sanctification before justification in the Institutes. This may have been to head off Roman Catholic charges that Protestant teaching on justification made good works redundant. But it reveals also just how closely the two were tied together in Calvin’s thought. The mediatorial person of Christ, together with the Holy Spirit binds the two together. ‘...the forensic and transforming benefits of salvation are inseparable because both are communicated to the believer in the same way through union with the mediatorial person of Christ by the power of the Holy Spirit’ (Evans). Calvin does not posit a particular ordo salutis with a single moment at which a divine declaration is announced.

Next: Union with Christ in Federal Calvinism