By the breath of God frost is given: and the breadth of the waters is straitened. By the breath of God frost is given - The freezing of water, though it is generally allowed to be the effect of cold, and has been carefully examined by the most eminent philosophers, is still involved in much mystery; and is a very proper subject to be produced among the great things which God doeth, and which we cannot comprehend, Job 37:5. Water, when frozen, becomes solid, and increases considerably in bulk. The expansive power in freezing is so great, that, if water be confined in a gun-barrel, it will split the solid metal throughout its whole length. Bombshells have been filled with water, and plugged tight, and exposed to cold air, when they have been rent, though the shell has been nearly two inches thick! Attempts have been made to account for this; but they have not, as yet, been generally successful. The breath of God freezes the waters; and that breath thaws them. It is the work of Omnipotence, and there, for the present, we must leave it.
The breadth of the waters is straitened - This has been variously translated; מוצק mutsak, which we here render straitened, we translate Job 37:18 melted. Mr. Good thinks that the idea of a mirror is implied, or something molten; and on this ground it may be descriptive of the state of water formed into ice. He therefore translates: -
By the blast of God the frost congealeth,
And the expanse of the waters into a mirror.
I have only to observe, that in the act of freezing wind or air is necessary; for it has been observed that water which lay low in ponds did not freeze till some slight current of air fell on and ruffled the surface, when it instantly shot into ice.