Ellicott's Commentary for English Readers - Genesis 1:8
(8) God called the firmament (the expanse) Heaven.—This is a Saxon word, and means something heaved up. The Hebrew probably means the heights, or upper regions, into which the walls of cities nevertheless ascend (Deuteronomy 1:28). In Genesis 1:1, “the heaven” may include the abysmal regions of space; here it means the atmosphere round our earth, which, at a distance of about forty-five miles from the surface, melts away into the imponderable ether. The work of the second day is not described... read more
Ellicott's Commentary for English Readers - Genesis 1:7
(7) God made the firmament.—This wide open expanse upon earth’s surface, supplied by the chemistry of nature—that is, of God—with that marvellous mixture of gases which form atmospheric air, was a primary necessity for man’s existence and activity. In each step of the narrative it is ever man that is in view; and even the weight of the superincumbent atmosphere is indispensable for the health and comfort of the human body, and for the keeping of all things in their place on earth. (See Note,... read more