1:5 Day. The use of “day” (Hebrew yom) in Genesis 1:5 is its first occurrence in Scripture, and here it is specifically defined by God as “the light” in the cyclical succession of light and darkness which has, ever since, constituted a solar day. Since the same word is used in defining all later “yoms” as used for this “first” yom, it is incontrovertible that God intends us to know that the days of creation week were of the same duration as any natural solar day. The word yom in the Old Testament almost always is used in this natural way, and is never used to mean any other definite time period than a literal day. This becomes especially clear when it is combined with an ordinal (e.g., “first day”) or with definite bounds (e.g., “evening and morning”), neither of which usages in the Old Testament allow non-literal meanings. It is occasionally, though rarely, used symbolically or in the sense of indefinite time (e.g., “the day of the Lord”), but such usage (as in English or other languages) is always evident from the context itself. Thus the so-called day-age theory, by which the days of creation are assumed to correspond to the ages of geology, is precluded by this definitive use of the word in its first occurrence, God Himself defining it!