are fixed in the firmament, as plants
are fixed in the earth. For, the Scripture says: "He set them in the
firmament." But plants are described as produced when the earth, to
which they are attached, received its form. The lights, therefore,
should have been produced at the same time as the firmament, that is
to say, on the second day.

Obj. 4: Further, plants are an effect of the sun, moon, and other
heavenly bodies. Now, cause precedes effect in the order of nature.
The lights, therefore, ought not to have been produced on the fourth
day, but on the third day.

Obj. 5: Further, as astronomers say, there are many stars larger than
the moon. Therefore the sun and the moon alone are not correctly
described as the "two great lights."

_On the contrary,_ Suffices the authority of Scripture.

_I answer that,_ In recapitulating the Divine works, Scripture says
(Gen. 2:1): "So the heavens and the earth were finished and all the
furniture of them," thereby indicating that the work was threefold.
In the first work, that of "creation," the heaven and the earth were
produced, but as yet without form. In the second, or work of
"distinction," the heaven and the earth were perfected, either by
adding substantial form to formless matter, as Augustine holds (Gen.
ad lit. ii, 11), or by giving them the order and beauty due to them,
as other holy writers suppose. To these two works is added the work
of adornment, which is distinct from perfect[ion]. For the perfection
of the heaven and the earth regards, seemingly, those things that
belong to them intrinsically, but the adornment, those that are
extrinsic, just as the perfection of a man lies in his proper parts
and forms, and his adornment, in clothing or such like. Now just as
distinction of certain things is made most evident by their local
movement, as separating one from another; so the work of adornment is
set forth by the production of things having movement in the heavens,
and upon the earth. But it has been stated above (Q. 69, A. 1), that
three things are recorded as created, namely, the heaven, the water,
and the earth; and these three received their form from the three
days' work of distinction, so that heaven was formed on the first
day; on the second day the waters were separated; and on the third
day, the earth was divided into sea and dry land. So also is it in
the work of adornment; on the first day of this work, which is the
fourth of creation, are produced the l