At this point a dialectic of in nobis and extra nos thinking is evident. On the one hand, the sacrificial work of Christ is accomplished outside the believer. In addition, the believer, although fully justified, is not made fully righteous in this life. In both these senses, the justification of the believer is to be found only extra nos. On the other hand, as Calvin so pointedly remarks at the beginning of Book III of the Institutio, "as long as Christ remains outside of us... all that he has suffered and done for the salvation of the human race remains useless and of no value to us." Whatever questions have been raised subsequently, it should be apparent that Calvin himself detected no contradiction here. Subjective incorporation and objective substitution are not mutually exclusive categories for Calvin. [William B. Evans, Imputation and Impartation: Union with Christ in American Reformed Theology (Eugene, OR: Wipf and Stock, 2008), 36]
John Calvin taught, in a dialectical manner, both justification by faith alone, and salvation by union with Christ, at least according to the claims of William Evans. Or to synthesize the statements, according to Evans' interpretation of Calvin, "the believer is justified through union with Christ and is united with Christ by faith and the Holy Spirit" (Ibid., 36). But when one actually checks the source material in Calvin's Institutes, what Evans claims to be there does not appear to be present. What are we to make of Calvin's understanding of salvation?
When Calvin claims that God has purchased salvation through Christ, he is speaking of redemption accomplished. Christ through His death on the Cross has purchased the redemption of His people. Subsequently, this redemption must be applied to those who believe. It is in this context that Calvin remarks why it is insufficient for Christ to be "outside of us." Evans interprets that as speaking of salvation by union with Christ in nobis (in us) as it were, but is that the right manner of interpretation?
Christ in accomplishing redemption purchased the double grace (duplex gratiam) of justification and sanctification (historically called "regeneration"). Christ is then given to us for our salvation. We note here that the focus is Christ given to us. Or from a third party point of view, it is for us. The phrase that best describes this giving of Christ is pro nobis (for us). In other words, Christ remains separate from the elect, but He is given for our benefit.
Evans' promotion of his theory of a substantial union with Christ therefore does not seem to be supported by the evidence. It is one thing to claim union with Christ in the sense of communion with Christ, which Calvin held to. But Christ given to His people pro nobis is indeed one type of communion, and substantial union in nobis is another type of communion. The question is why we must take Calvin as teaching the second type of communion, as what Evans is arguing for, as opposed to the first type, which seems to be the plain reading of Calvin's work. Proving Calvin held to a type of union with Christ is therefore insufficient for Evans' case, and thus so far I see no reason why I should believe Evans' version of union with Christ.