Genesis 1:12

When I hear "grass," I think of grass, and in the same manner I understand everything as it is said: a plant, a fish, a wild animal and an ox. Indeed, "I am not ashamed of the gospel." … (Some) have attempted by false arguments and allegorical interpretations to bestow on the Scripture a dignity of their own imagining. But theirs is the attitude of one who considers himself wiser than the revelations of the Spirit and introduces his own ideas in pretense of an explanation. Therefore, let it be understood as it has been written.

And to such a degree has the Holy Ghost made this the rule of His Scripture, that whenever anything is made out of anything, He mentions both the thing that is made and the thing of which it is made. "Let the earth," says He, "bring forth grass, the herb yielding seed, and the fruit-tree yielding fruit after its kind, whose seed is in itself, after its kind. And it was so. And the earth brought forth grass, and herb yielding seed after its kind, and the tree yielding fruit, whose seed was in itself, after its kind." ... If the Holy Ghost took upon Himself so great a concern for our instruction, that we might know from what everything was produced, would He not in like manner have kept us well informed about both the heaven and the earth, by indicating to us what it was that He made them of, if their original consisted of any material substance?

For, whereas we learn from Scripture in the account of the first Creation, that first the earth brought forth "the green herb" (as the narrative says), and that then from this plant seed was yielded, from which, when it was shed on the ground, the same form of the original plant again sprang up, the Apostle, it is to be observed, declares that this very same thing happens in the Resurrection also; and so we learn from him the fact, not only that our humanity will be then changed into something nobler, but also that what we have therein to expect is nothing else than that which was at the beginning. In the beginning, we see, it was not an ear rising from a grain, but a grain coming from an ear, and, after that, the ear grows round the grain: and so the order indicated in this similitude clearly shows that all that blessed state, which arises for us by means of the Resurrection is only a return to our pristine state of grace.

Although the grasses were only a moment old at their creation, they appeared as if they were months old. Likewise, the trees, although only a day old when they sprouted forth, were nevertheless like trees years old as they were fully grown and fruits were …

Hence Scripture shows you everything completed before the creation of this body [the sun] lest you attribute the production of the crops to it instead of to the Creator of all things.