Selection from Arcana Coelestia ~ Emanuel Swedenborg
It is said in the church that from the three who are called "Father, Son, and Holy Spirit," there comes forth one Divine, which is also called "one God;" and that from the Father proceeds the Son, and from the Father through the Son proceeds the Holy Spirit; but what this proceeding or going forth means, is as yet unknown.The ideas of the angels on this subject are quite different from those of the men of the church who have thought about it, for the reason that the ideas of the men of the church are founded upon three, but those of the angels upon one. That the ideas of the men of the church are founded upon three, is because they distinguish the Divine into three persons, and attribute to each one special and particular offices. Hence they can indeed say that God is one, but they cannot possibly think otherwise than that there are three, who, by a union which they call mystical, are one. In this way they may indeed be able to think that there is one Divine, but not that there is one God; for in their thought the Father is God, the Son is God, and the Holy Spirit is God. One Divine is one by agreement and thus unanimity; but one God is absolutely one.
The kind of idea or thought a man of the church has about the one God, is clearly manifest in the other life, for everyone carries with him the ideas of his thought. The idea or thought of such people is that there are three gods; yet they dare not say "gods," but "God."
A few also make one out of three by union; for they think in one way of the Father, in another way of the Son, and in another way of the Holy Spirit. From this has clearly appeared the nature of the faith the church has about the most essential thing of all, which is the Divine Itself; and as in the other life all are conjoined or separated by the thoughts which are of faith, and the affections which are of love, therefore those who have been born outside the church, and have believed in one God, flee from those who are within the church, saying of them that they do not believe in one God, but in three gods; and that those who do not believe in one God under a human form do not believe in any God, because their thought pours itself forth into the universe, without determination, and thus falls down into nature; which they thus acknowledge in the place of God.
When asked what they mean by "proceeding," in saying that the Son proceeds from the Father and that the Holy Spirit proceeds from the Father through the Son, they answer that "proceeding" is a term of union, and that it wraps up this mystery within it. But their idea of thought about this, when examined, has been found to be that of a mere word, devoid of reality.
But the ideas of the angels about the Divine, the Trinity, and Proceeding, are quite different from the ideas of the men of the church, for the reason, as said above, that the ideas of thought of the angels are founded upon one, whereas the ideas of thought of the men of the church are founded upon three.
The angels think (and what they think they believe) that there is one God, and that He is the Lord; that His Human is the Divine Itself in a form; and that the holy proceeding from Him is the Holy Spirit; thus that there is a Trinity, but still it is One.
A notion of this is obtained from the idea that exists about the angels in heaven:
An angel appears there in the human form, but still there are three things in him that make a one. There is his internal, which does not appear before the eyes; there is the external, which does appear; and there is the sphere of life of his affections and thoughts, which pours out from him to a distance. These three make one angel. But the angels are finite and created, whereas the Lord is infinite and uncreated. And as no man, or even angel, can have any idea about the Infinite except from things finite, therefore such an example may be given in order to illustrate what the Trinity in One is; and that there is one God; and that He is the Lord, and no other.
(Arcana Coelestia 9303)