Much has been written about the length of the days of creation, whether they were ordinary days of around twenty-fours hours duration, long ages, some combination of days and ages, or simply a nonhistorical literary framework or mnemonic device intended to serve as the means whereby information about the divine activity in creation might be presented in an aesthetically pleasing and helpful fashion. I can discern no reason, either from Scripture or from the human sciences, for departing from the view that the days of Genesis were ordinary twenty-four-hour days. The following points favor this view:
1. The word “day” (יוֹם, yôm), in the singular, dual and plural, occurs some 2,225 times in the Old Testament with the overwhelming preponderance of these occurrences designating the ordinary daily cycle. Normally, the preponderate meaning of a term should be maintained unless contextual considerations force one to another view. As Robert Lewis Dabney states with respect to the meaning of יוֹם, yôm, in Genesis 1: “The narrative [of Genesis 1] seems historical, and not symbolical; and hence the strong initial presumption is, that all its parts are to be taken in their obvious sense.… The natural day is [yôm˓s] literal and primary meaning. Now, it is apprehended that in construing any document, while we are ready to adopt, at the demand of the context, the derived or tropical meaning, we revert to the ordinary one, when no such demand exists in the context.” No such contextual demand exists in Genesis 1.
2. The recurring phrase, “and the evening and the morning [taken together] constituted day one, etc.” (1:5, 8, 13, 19, 23, 31), suggests as much. The qualifying words, “evening and morning,” attached here to each of these recurring statements occur together outside of Genesis in 30 verses (e.g., Exod. 18:13; 27:21). In each instance these words are employed to describe an ordinary day.
3. In the 476 other cases in the Old Testament where יוֹם, yôm, stands in conjunction with a cardinal or an ordinal number, e.g., Exodus 12:15; 24:16; Leviticus 12:3, it never means anything other than a normal, literal day.
4. With the creation of the sun “to rule the day” and the moon “to rule the night” occurring on the fourth day (Gen. 1:16–18), days four through six would almost certainly have been ordinary days. This would suggest that the seventh would also have been an ordinary day. All this would suggest in turn, if we may assume that the earth was turning on its axis at that time, that days one through three would have been ordinary days as well.
5. If we follow the analogia Scripturae principle of hermeneutics enunciated in the Westminster Confession of Faith to the effect that “the infallible rule of interpretation of Scripture is the Scripture itself: and therefore, when there is a question about the true and full sense of any Scripture (which is not manifold, but one), it must be searched and known by other places that speak more clearly” (I/ix), then the “ordinary day” view has most to commend it since Moses grounds the commandment regarding seventh-day Sabbath observance in the fact of the divine Exemplar’s activity: “In six days the Lord made the heavens and the earth, the sea, and all that is in them, but he rested on the seventh day. Therefore the Lord blessed the Sabbath day and made it holy” (Exod. 20:11; see also 31:15–17).
6. In the 858 occurrences of the plural “days” (יָמִים, yāmîm) in the Old Testament (see Exod. 20:11), their referents are always ordinary days. Ages are never expressed by the word יָמִים, yāmîm.
7. Finally, had Moses intended to express the idea of seven “ages” in Genesis 1 he could have employed the term עוֹלָם, ˓ôlām, which means “age” or “period of indeterminate duration.””