Selections from Apocalypse Explained ~ Emanuel Swedenborg
There are two things that can be predicated only of Jehovah, that is, the Lord, namely, infinity and eternity; infinity of His esse, which is the Divine good of His Divine love; eternity of His existere from that esse, which is the Divine truth of His Divine wisdom. These two are Divine in themselves. Out of these the universe was created; consequently, all things in the universe are referable to good and to truth, and good everywhere is the esse of a thing, and truth is the existere therefrom; but these two in all things of the universe are finite.---
All times in the Word signify not times but states of life, and as all times signify states of life, so in reference to the Lord they signify infinite state, and infinite state as to time is eternity. That all times are comprised in "who is, and who was, and who is to come," is evident.
Of eternity, which is of the Lord alone, many things might be said; but such things are not understood by the natural man, whose thoughts are chiefly based on time, space, and matter, while, nevertheless, eternity, in itself, does not include such things. If, indeed, man could think of eternity as the angels of heaven do, he might arrive at some idea of it, and thus might comprehend what from eternity is, which is signified by "who was;" also what the Divine foresight is, that it is in the most particular things from eternity; and what Divine Providence is, that it is in the most particular things to eternity; consequently, that whatsoever proceeds from the Lord is from eternity to eternity; and unless it were so heaven and the universe would not subsist.
Let it be known, that the like is meant by "Jehovah" as by "who is, who was, and who is to come," since "Is," which is the meaning of Jehovah, involves what precedes, that is, "who was," and also what is future, that is, "who is to come," and thus signifies from eternity to eternity.
That "Is," signifies from eternity is also known in the Christian world from the Psalm of David, where it is said: I will declare of the decree; Jehovah said unto me; thou art My son; this day have I begotten thee (Ps. 2:7) — it is known that these things are said of the Lord, and that by "today" is meant from eternity. (That by "tomorrow," also in the Word, where the Lord is treated of, is signified to eternity.)
That the words "who is," "who was," and "who is to come," signify also the All in all things of heaven and the church is because they signify eternity; and in heaven, eternity can be expressed by no other word than Divine, for the reason that what is infinite cannot fall into the angelic idea, and still less into a human idea; and eternity is infinite Existere from infinite Esse; but only this enters the idea, that eternity, which is the Divine in respect to Existere, is the All in all things of heaven and of the church. For the whole heaven is heaven not from the angels' proprium [selfhood, or what is their own], but from the Divine of the Lord; nor is the church the church from the proprium of men, but from the Divine of the Lord; for all the good of love and the truth of faith are from the Lord, and it is the good of love and the truth of faith that make heaven and the church. Angels and men are only recipients, and so far as they receive, heaven and the church are in them.
(Selections from Apocalypse Explained 286; 23)