Genesis 1:5

And God called That God should give names to things is to our minds a strange and almost unintelligible thought. To the Hebrews, on the contrary, it seemed a natural feature of the story. To them the Hebrew language was that in which the Divine Will was expressed; and, to their minds, the Hebrew name and the thing which it designated had been rendered inseparable by Divine Decree on the day of its creation.

Observe that the names "Day" and "Night" are given to "light" and "darkness," although the heavenly bodies are not made until the fourth day.

and there was The "day" with the Hebrews began in the evening. It was reckoned from 6 p.m. to 6 p.m. The Israelite writer, therefore, in speaking of the days of Creation, describes them as ordinary days with their succession of evening and morning. There is no need to suppose, as some have done, that the "evening" in this verse refers to the pre-existent darkness of Genesis 1:2, and that "morning" denotes the period of light before the creative work of the second day. In the mention of the days, the Hebrew story of Creation is perfectly simple and natural. With childlike faith, it told how the Creator completed His work in a time corresponding to six earthly days, each consisting of evening and morning. The hallowing of the seventh day, in chap. Genesis 2:2-3, presupposes the literal character of the previous six days.

Suggestions have frequently been made in the course of the last half century, that each of the six days is to be understood as a period of indefinite duration. But it is important to remember that the facts, with which modern science has familiarized us, respecting the antiquity of the earth, as shewn by geology, and our solar system, as shewn by astronomy, were wholly unknown until quite recent times. We must be careful, therefore, not to read back such notions into the minds of the writer and of those for whom he wrote this chapter. The assumption that the inspired record must be literally accurate has led to much misinterpretation of Scripture as well as to great mental confusion and religious distress.

The difficulties, which have been felt with regard to the mention of "days," have arisen from the natural wish to reconcile the plain and childlike language of ancient unscientific Semitic story, which accounted for the origin of the world, with the abstruse and dazzling discoveries of modern Physical Science. The two must be kept absolutely distinct.

one day So the Hebrew, not "the first day"; but "one day," LXX ἡμέρα μία, Lat. dies unus.