The following remark does not form an essential part of our present research; it will nevertheless be found useful in the course of this discussion. Many scholars do not know what time really is, and men like Galen were so perplexed about it that they asked whether time has a real existence or not; the reason for this uncertainty is to be found in the circumstance that time is an accident of an accident. Accidents which are directly connected with material bodies, e.g., colour and taste, are easily understood, and correct notions are formed of them. There are, however, accidents which are connected with other accidents, e.g., the splendour of colour, or the inclination and the curvature of a line; of these it is very difficult to form a correct notion, especially when the accident which forms the substratum for the other accident is not constant but variable. Both difficulties are present in the notion of time: it is an accident of motion, which is itself an accident of a moving object; besides, it is not a fixed property; on the contrary, its true and essential condition is, not to remain in the same state for two consecutive moments. This is the source of ignorance about the nature of time. We consider time a thing created; it comes into existence in the same manner as other accidents, and the substances which form the substratum for the accidents. For this reason, viz., because time belongs to the things created, it cannot be said that God produced the Universe in the beginning. Consider this well; for he who does not understand it is unable to refute forcible objections raised against the theory of Creatio ex nihilo. If you admit the existence of time before the Creation, you will be compelled to accept the theory of the Eternity of the Universe. For time is an accident and requires a substratum. You will therefore have to assume that something [beside God] existed before this Universe was created, an assumption which it is our duty to oppose. This is the first theory, and it is undoubtedly a fundamental principle of the Law of our teacher Moses; it is next in importance to the principle of God’s unity. Do not follow any other theory. Abraham, our father, was the first that taught it, after he had established it by philosophical research. He proclaimed, therefore, “the name of the Lord the God of the Universe” (Gen. xxi. 33); and he had previously expressed this theory in the words, “The Possessor of heaven and earth” (ibid. xiv. 22).