Then the LORD answered Job out of the whirlwind and said:
Let us observe here, 1. Who speaks - The Lord, Jehovah, not a created angel, but the eternal Word himself, the second person in the blessed Trinity, for it is he by whom the worlds were made, and that was no other than the Son of God. The same speaks here that afterwards spoke from Mount Sinai.
Commenting on Job 38:1-3
Then the Lord answered Job out of the whirlwind,.... As soon as Elihu had done speaking, who saw the tempest rising, and gave hints of it, Job 37:2; and hastened to finish his discourse. This was raised to give notice of the Lord being about to appear, and to display his majesty, and to command reverence and attention.
Then the LORD answered Job out of the whirlwind, and said, (a) That his words might have greater majesty, and that Job might know with whom he had to do.