of time follows movement, as appears from the preceding article.
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.

Reply Obj. 1: The "now" that stands still, is said to make eternity
according to our apprehension. As the apprehension of time is caused
in us by the fact that we apprehend the flow of the "now," so the
apprehension of eternity is caused in us by our apprehending the
"now" standing still. When Augustine says that "God is the author of
eternity," this is to be understood of participated eternity. For God
communicates His eternity to some in the same way as He communicates
His immutability.

Reply Obj. 2: From this appears the answer to the Second Objection.
For God is said to be before eternity, according as it is shared by
immaterial substances. Hence, also, in the same book, it is said that
"intelligence is equal to eternity." In the words of Exodus, "The
Lord shall reign for eternity, and beyond," eternity stands for age,
as another rendering has it. Thus it is said that the Lord will reign
beyond eternity, inasmuch as He endures beyond every age, i.e. beyond
every kind of duration. For age is nothing more than the period of
each thing, as is said in the book _De Coelo_ i. Or to reign beyond
eternity can be taken to mean that if any other thing were conceived
to exist for ever, as the movement of the heavens according to some
philosophers, then God would still reign beyond, inasmuch as His
reign is simultaneously whole.

Reply Obj. 3: Eternity is nothing else but God Himself. Hence God is
not called eternal, as if He were in any way measured; but the idea
of measurement is there taken according to the apprehension of our
mind alone.

Reply Obj. 4: Words denoting different times are applied to God,
because His eternity includes all times; not as if He Himself were
altered through present, past and future.
_______________________

THIRD ARTICLE [I, Q. 10, Art. 3]

Whether to Be Eternal Belongs to God Alone?

Objection 1: It seems that it does not belong to God alone to be
eternal. For it is written that "those who instruct many to justice,"
shall be "as stars unto perpetual eternities [*Douay: 'for all
eternity']" (Dan. 12:3). Now if God alone we