In a previous post we looked at a snippet from John Edwards of Cambridge (1637-1716) on the believer’s union with Christ as the foundation of double imputation. The same doctrine can be seen beautifully treated by another Reformed conforming churchman, Ezekiel Hopkins (1634-1690), Bishop of Derry in Ireland, in his posthumously published The Doctrine of the Two Covenants (1712, p. 52-53):
…Faith gives us a title to the righteousness of Christ, and makes it ours not only by the promise of God, but as it is the bond of union between Christ and the soul. By faith it is that we are made mystically one with Christ, living members in his body, fruitful branches of that heavenly and spiritual vine. We have the communication of the same name. So also is Christ, saith the Apostle (1 Cor. 12:12), speaking there of Christ mystical, both his Person and his Church. We have the same relations, I ascend to my Father and to your Father (John 20:17). We are made partakers of the same Spirit, for if any man have not the Spirit of Christ he is none of his (Rom. 8:9), he that is joined to the Lord is one Spirit (1 Cor. 6:17). And finally, the very life that we live is said not to be ours, but Christ liveth in us, and that we live by the faith of the Son of God (Gal. 2:20). So that being thus one with Christ, his righteousness becomes our righteousness, even as our sins became his: and God deals with Christ and believers, as if they were one person. The sins of believers are charg’d upon Christ, as though they were his; and the righteousness of Christ is reckoned to believers as theirs: neither is God unjust either in the one, or the other imputation, because they are mystically one; and this mystical union is a sufficient ground for imputation. Yet from this union flows the participation only of the benefits of his mediatorship: for we are not hereby transubstantiated or deify’d, as some of late years have blasphemously conceited; neither the Godhead of Christ, nor his essential righteousness as God, nor his divine and infinite properties are made ours; but only the fruits and effects of his mediation: so that hereupon God graciously accounts of us as if we had done in our own persons, whatsoever Christ hath done for us, because by faith Christ and we are made one.
Later on he offers a further discussion of this doctrine, this time drawing on the biblical imagery of the marriage between Christ and believers (p. 186-188):
Faith makes the righteousness of Christ to be ours, as it is the bond of that mystical union that there is between Christ and the believing soul. If Christ and the believer be one, the righteousness of Christ may well be reckoned as the righteousness of the believer. Nay, mutual imputation flows from mystical union: the sins of believers are imputed to Christ, and the righteousness of Christ to them; and both justly, because being united each to [the] other by a mutual consent (which consent on our part is faith) God considers them but as one person. As it is in marriage, the husband stands liable to the wife’s debts, and the wife stands interested in her husband’s possessions, so it is here: faith is the marriage-band and tie between Christ and a believer; and therefore all the debts of a believer are chargeable upon Christ, and the righteousness of Christ is instated upon the believer: so that upon the account of this marriage-union he hath a legal right and title to the purchase made by it. Indeed this union is an high and inscrutable mystery, yet plain it is that there is such [a] close, spiritual, and real union between Christ and a believer. The Scripture often both expressly affirms it, He that is joined to the Lord is one spirit (1 Cor. 6:17); and also lively illustrates it by several resemblances. It is likewise plain that the band of this union on the believer’s part is faith: consult Rom. 11:17 with 11:20. And therefore from the nearness of this union there follows a communication of interests and concerns: insomuch that the Church is called Christ (1 Cor. 12:12, so also is Christ), and their sufferings called the sufferings of Christ (Col. 1:24; Acts 9:4). So likewise from this mystical union the sins of believers are laid upon Christ, and his righteousness imputed unto them: see this as to both parts: He hath made him to be sin for us, who knew no sin, that we might be made the righteousness of God in him (2 Cor. 5:21) and He hath redeemed us from the curse of the law, being made a curse for us, that the blessing of Abraham might come upon us (Gal. 3:13-14). It is still upon the account of this union that Christ was reckoned a sinner, and we are reckoned as righteous. And therefore as faith is the bond and tye of this union, so it is, without more difficulty, the way and means of our justification. By faith we are united unto Christ; by that union we have truly a righteousness; and upon that righteousness the justice of God, as well as his mercy, is engaged to justifie and acquit us.