Section 1. Definition of Eternity.

Eternity is the simultaneously whole and perfect possession of interminable life.

As we attain to the knowledge of simple things by way of compound things, so must we reach to the knowledge of eternity by means of time, which is nothing but the numbering of movement by before and after. For since succession occurs in every movement, and one part comes after another, the fact that we reckon before and after in movement, makes us apprehend time, which is nothing else but the measure of before and after in movement. Now in a thing bereft of movement, which is always the same, there is no before or after. As therefore the idea of time consists in the numbering of before and after in movement; so likewise in the apprehension of the uniformity of what is outside of movement, consists the idea of eternity.

Further, those things are said to be measured by time which have a beginning and an end in time, because in everything which is moved there is a beginning, and there is an end. But as whatever is wholly immutable can have no succession, so it has no beginning, and no end.

Thus eternity is known from two sources: first, because what is eternal is interminable—that is, has no beginning nor end (that is, no term either way); secondly, because eternity has no succession, being simultaneously whole.

Section 2. Eternity of God.

The Father is eternal, the Son is eternal, the Holy Spirit is eternal.

The idea of eternity follows immutability, as the idea of time follows movement, as appears from the preceding section. Hence, as God is supremely immutable, it supremely belongs to Him to be eternal. Nor is He eternal only; but He is His own eternity; whereas, no other being is its own duration, as no other is its own being. Now God is His own uniform being; and hence as He is His own essence, so He is His own eternity.

Section 3. God's Sole Possession of Eternity.

God is the only one eternal. God is the only one who has no beginning. Now whatever has a beginning, is not eternal.

Eternity truly and properly so called is in God alone, because eternity follows on immutability; as appears from the first article. But God alone is altogether immutable, as was shown above. Accordingly, however, as some receive immutability from Him, they share in His eternity. Thus some receive immutability from God in the way of never ceasing to exist; in that sense it is said of the earth, it stands for ever. Again, some things are called eternal in Scripture because of the length of their duration, although they are in nature corruptible; thus (Psalm 75:5) the hills are called eternal and we read of the fruits of the eternal hills. (Deuteronomy 33:15). Some again, share more fully than others in the nature of eternity, inasmuch as they possess unchangeableness either in being or further still in operation; like the angels, and the blessed, who enjoy the Word, because as regards that vision of the Word, no changing thoughts exist in the Saints. Hence those who see God are said to have eternal life; This is eternal life, that they may know You the only true God (John 17:3).