II.1 chapter 7

What were these days of creation like?
God created the light on the first day, and made the movement of it that made morning and evening. How this exactly happened we cannot say. We can however understand allegorical about it that the knowledge of God in comparison with the knowledge of us is like the light of the morning to the evening. (Our knowledge is not the opposite, like the night to the morning, but a modification of it.) And when our knowledge is directed to praise and love of the Creator, it will return to the light of the morning.
In this way we can see the first day as the return to the knowledge of God; the second to the knowledge of the heaven, the third to the knowledge of the earth, the fourth to the knowledge of the heavenly lights, the fifth to the knowledge of the fishes and birds, the sixth to the knowledge of man.