By the breath of God frost is given - Not by the violent north wind, or by the whirlwind of the south, but God seems to “breathe” in a gentle manner, and the earth is covered with hoary frost. It appears in a still night, when there is no storm or tempest, and descends upon the earth as silently as if it were produced by mere breathing. Frost is congealed or frozen dew. On the formation and cause of dew, see the notes at Job 38:28. The figure is poetical and beautiful. The slight motion of the air, even when the frost appears, seems to be caused by the breathing of God.
And the breadth of the waters is straitened - That is, is contracted by the cold; or is frozen over. The waters are “compressed” into a solid mass (במוצק bemûtsaq), or are in a state of “pressure” or “compression” - or so the word used here means. What were before expanded rivers or arms of the sea, are now compressed into solid masses of ice. This, also, is proof of the greatness and power of God, for though the cause was not understood by Elihu, yet there was no doubt that it was produced by his agency. Though the laws by which this occurs are now better understood than they were then, it is no less clearly seen that it is by his agency; and all the light which we obtain in regard to the laws by which these things occur, only serve to exalt our conceptions of the wisdom and greatness of God.