This a (very rough) translation of sections of David Hollaz’s chapter on mystical union in his Examin Theologicum Acroamaticum.
On Indwelling Grace
I. What is the Mystical Union with God?
Mystical union is the spiritual conjunction of the Triune God with justified man, wherein like the temple, God consecrates with his particular being, as a substantial home with his gracious influence.
Describe this more fully.
Mystical union is the application of grace, of the Triune God, out of a special love, in view of the merits of Christ, that is apprehended in true faith, wherein the one in a regenerate and justified state is consecrated as a temple, the presence of a substantial indwelling fulfills all of the fullness of his gifts, he works in a special meeting, as, the presence of a certain grace and future glory, in union with Christ and in the church, with sanctification, and eternal salvation.
The time of the mystical union with regeneration, justification, and renovation is all the same; for these results all occur together in an instant; for at the same time man is regenerated and justified, he connects himself with God and in this union. Nevertheless, one is prior as to our various ways of accounting. Thus regeneration and justification are prior to this union as that which is through faith, and finally having received faith in regeneration, and sins that are forgiven hinder the union of grace. But union is prior to renovation; the effect of this is the good that I will work, and through the latter I will recognize the former.
Though mystical union, where God inhabits man as in a temple, according to our mode of understanding comes after justification according to the order of nature; however, I must confess that the formal union of faith, by which Christ is apprehended, put on, and united with us, where Christ is the mediator and conveyer of grace, and the remission of sins, is prior to justification. For as faith is prior to justification, insofar as the merit of Christ is received and is united with us to become ours. “If we take the spiritual regeneration, the rebirth wrought by God, as consisting mainly in our union with Christ, this differs from justification as an effect to a cause. For we are justified because we are from God, or because we are in Christ,” see Rom. 8:1: “For there is now no condemnation for those who are in Christ Jesus.” The righteousness of Christ is the chief spiritual benefit reckoned to those who believe being closely united to him, his members, who are found in him, Phil. 3:9.
II. How many kinds of union of God with men are there?
The union of God with man is twofold: a. general, by which all the faithful and unbelievers in God live, move, and have their being, and b. special, by which God by grace is substantially here more in the people of the church militant, and now works in this special meeting, and the glory of God’s elect in the church triumphant, wherein they are filled with the surpassing fullness of grace.
III. What is the spiritual and mystical union of the soul that is wrought?
This is why mystical union, the mystery is astonishing, that the boundless and infinite God dwells within the human heart. It is called spiritual; since the Spirit of grace inhabits the reborn, not in the flesh, not in the physical, but the spiritual and supernatural perfection.
IV. In what ways is the name mystical union used?
V. What words are used for mystical union in Holy Scripture?
There are many fine phrases in Sacred Scripture for mystical union, which are described. It is called: a. the betrothal of believers to Christ, b. the mystical marriage of Christ to the church c. members of the head, d. granting of the branches into the spiritual life of Christ, e. the dwelling of the Trinity in the regenerated man.
VI. Who completes the mystical union?
The efficient cause of the mystical union is the Holy Trinity a. the Father, b. the Son, c. the Holy Spirit.
VII. What impels God to connect himself to the reborn?
In order for the reborn to be joined to God by mystical union, a. God has a special internal love by which he will embrace them, b. the external merits of Christ, and the true faith by which man apprehends it.
VIII. By what means does the mystical union of God come to the regenerate man?
The means on the part of God which are efficient and confirm the mystical union are: a. the word of the gospel b. baptism, c. God being embraced in faith. The act on the part of man that receives it is faith.
IX. What is the ministerial cause of the mystical union with God?
The heralds of the Sacred Ministry are wedding assistants, bringing the bride into this spiritual pairing in union with Christ.
X. What are the natures, of which this mystical union connects?
On the one hand is a. the entire substance of the Holy Trinity, b. the substance of the human nature of Christ, c. on the other side is the substance of regenerate man, c. considered in body and soul.
XI. In what does the mystical union consist?
In both a special and intrinsic connection, a. of the substance of man with the substance of the Holy Trinity and the body of Christ, b. also, in the gracious working in which God with his benevolent influence is working specially and effectively in regenerate man.
XII. Now can you clearly explain what the spiritual union of God with the regenerate consists in?
Mystical union is substantial a. but it is not formally substantial, b. with the person, but not in respect to the personal boundaries to which, c. it is accidental, not of their end, but to the terminus they have; d. it is not a mere external communication, but perichoretic, being immanent and mutual , e. not the bare essence, but the energetic presence of God, or operative f. finally, the union of God with man is harmonious with the faithful , or a joining that brings about the proper tempering of the affections.
XIII. What is the goal of mystical union?
a. The ultimate goal of mystical union is eternal life, b. the intermediate ends and effects are: communion with God the Father, Son, and Holy Spirit, c. the assurance of faith, d. divine assistance, e. effective comfort, f. the awakening of prayers and their being heard, g. conservation in a state of grace, and from this is born perseverance h. sanctification, i. the reception of the glory of the resurrection and eternal blessedness, j. and union with the regenerate and the union of the church.
XIV. What can dissolve the mystical union?
The mystical union can be dissolved by a. falling into unbelief, b. a life of impiety.
XV. What aspects of mystical union should be included in preaching?
Preaching on the mystical union should discuss a. how it is appropriated, and b. its cause.