γ. The three Persons also agree in Ἐμπεριχωρήσει/ emperichoresis, or mutual Inexistence/Interpenetration, as the Fathers say. Again, Curcellæus carps at this expression, Quaternione Dissertationum adversus Maresium, DissertationI, § 69, as ἄγραφον/unwritten, ambiguous, and what is used to signify a thing that is nowhere taught in Scripture. At the same time, the Fathers in this manner only wished to express that most perfect Union of the Divine Persons among themselves; whereby, although they remain ever distinct, they are never separated from each other, but embrace one another in intimate union. Which matter, 1. spontaneously flows from the numeric Unity of the Essence common to the three Persons: 2. is supposed in the simultaneous knowledge of the Father and the Son, which the Lord inculcates, John 14:8, 9; on which passage see, if you please, ARNOLDI’S Refutationem Catecheseos Racovianæ, page 318, § IX-XIII, ad Catechesem Racovianam de Cognitione Personæ Christi, chapter I, questions80, 81, pages 109, 110. And, 3. with respect to the thing signified, it is expressly taught in John 10:38; 14:10, 11, where it is said, ἐγὼ ἐν τῷ Πατρί, καὶ ὁ Πατὴρ ἐν ἐμοί ἐστι, I am in the Father, and the Father in me; likewise, ὁ Πατὴρ ἐν ἐμοὶ μένων, the Father that dwelleth in me.
It does not then follow that, because believers are said to be and to abide in God, John 17:21, 23; 1 John 3:24, hence there is also an ἐμπεριχώρησιν/emperichoresis of this sort is between them and God. The manner of the mystical Union of believers with God through the internal presence of the Spirit, who is the closest bond of their communion with God, differs much from the natural Union of the Divine Persons among themselves, with which the other union of believers with God is compared on account of slight analogy only: see MARESIUS’ Defensionem Fidei Catholicæ adversum Curcellæi Quaternionem, Dissertation I, section XI, § 38, numbers 17-29, pages 204, 208-212; BULL’S Defensionem Fidei Nicænæ, section IV, chapter IV, § 9-14, pages 284-290.
Moreover, our AUTHOR wishes ἐμπεριχώρησιν/emperichoresis to be distinguished from all Μεταγγισμῷ/Transmigration; those asserting which were called Metangismonites, “saying that the Son is in the Father in just the same way as a vessel is in another vessel, carnally supposing two bodies, as it were, in such a way that Son was in the Father, as a smaller vessel is in a larger,” which are the words of AUGUSTINE, de Hæresibus, chapter LVIII. The time and author of this heresy lies hidden, yet it appears to be referred to the Fourth Century by Danæus.
Now, this thesis concerning the Agreement of the Divine Persons in One Essence, Ἰσότητι/Equality, and Ἐμπεριχωρήσει/ emperichoresis, mutual Inexistence, is to be held against all the enemies, ancient and more recent, of the Deity of the Son and of the Holy Spirit.
In particular, to be noted here is Maty, Pastor of the Walloon Church, who in the year 1729 published a new System of the Trinity, againt whom ARMAND DE LA CHAPELLE, Pastor of the Hague, set himself in opposition: because Maty was unwilling to repudiate it, he was deprived of his office and ecclesiastical communion by the Wallonic Synod. This System is reviewed, together with the strictures against it, and the defense of the sentence of the Wallonic Synod, by the Reverend BONVOUST, Pastor at Utrecht,in his French tractate, le Triomphe de la Verite et de la Paix, pages326 and following. The opinion of Maty is summarily reduced to this: He believes that the First Person of the Trinity, namely, the Father, alone has that unique nature, namely, the Divine. But he thinks that in the Persons of the Son and Spirit two natures are yielded, one Divine, the other finite of an intelligent Spirit. These two spiritual Essences the Father produced before the foundation of the world, and assumed into the communion of His divine Essence, and thence resulted the second and third Persons of the Son and the Holy Spirit.
Maty acknowledges that that hypothesis, in which he assigns to the Holy Spirit a finite nature, joined to the Divine Nature, is not formally contained in Sacred Scripture: nevertheless, he assumes the same as necessary for the explanation of passages that treat of the mystery of the Trinity.
Maty concedes that from this System it follows that two Natures met in Christ already before the Incarnation, one divine, the other created, which he calls Angelic.
But he does not know, whether in the Incarnation this Angelic Nature is the Soul of the Body of Christ; or, with the Nature remaining truly Angelic, there is in Christ after the Incarnation a threefold Nature, Divine, Angelic, and Human.
He believes that the second Person is called the Son of God, because He is begotten, not as God, but as a finite, intelligent Essence.