Genesis 2:3

And God said, Let there be light] A sublime sentence! 'By the word of the Lord were the heavens made.' Light and darkness are regarded as two objects, each occupying a place of its own (Job 38:19). Light is created on the first day, the luminaries on the fourth. Not as an explanation, for this it is not, but merely as an illustration, it may be remembered that, according to the generally approved modern theory, the matter composing our solar system existed at first in the shape of an inconceivably vast mass of fiery vapour, which gradually cooled down and took the form of a rotating sphere. This threw off the planets, our earth amongst the number. The central part is now the sun. So that light in itself may be regarded as prior to the specific lights that stood related as luminaries to the earth. The earth by slow stages grew fit to be the abode of life.

God blessed the seventh day and sanctified (RV 'hallowed') it] This is adduced in Exodus as the ground for the observance of the sabbath (see Exodus 20:8 notes, Exodus 31:17; Hebrews 4:4). It was separated from ordinary days, and set apart as a day for rest, and at a later time for holy observance. Further instructions as to its use will be found in Exodus 31:13; Exodus 36:2; The Babylonians observed the 7th, 14th, 19th, 21st and 28th days of the lunar month, as days when men were subjected to certain restrictions: the King was not to eat food prepared by fire, nor offer sacrifice, nor consult an oracle, nor invoke curses on his enemies. But the weekly sabbath came to have a peculiar religious significance among the Hebrews, which is not evident among other nations; and by its regular recurrence every seventh day it was dissociated from its connexion with the moon, and with lunar superstitions.