Book 1 · Section 19

VIII. (19) "This is the book of the generation of heaven and earth, when they were Created." This is perfect reason, which is put in motion in accordance with the number seven, being the beginning of the creation of that mind which was arranged according to the ideas, and also of the sensation arranged according to the ideas, and perceptible only by the intellect, if one can speak in such a manner. And Moses calls the word of God a book, in which it is come to pass that the formations of other things are written down and engraved. (20) But, lest you should imagine that the Deity does anything according to definite periods of time, while you should rather think that everything done by him is inscrutable in its nature, uncertain, unknown to, and incomprehensible by the race of mortal men. Moses adds the words, "when they were created," not defining the time when by any exact limitation, for what has been made by the Author of all things has no limitation. And in this way the idea is excluded, that the universe was created in six days.