After Elihu's speech, the LORD appears to Job in a whirlwind. His three friends had spoken their minds and had become silent after Job made his long speech in defence of himself, and Elihu had spoken out his indignation at Job's criticism of God.
There was no more they could add, and it was then that the LORD came to put a close to the arguments, showing Job how he lacked knowledge and understanding. Virtually all His speech was addressed to Job, but at the end He also addressed Job's three friends (Job 42:7-8) so they possibly saw Him as Job did (42:5). What a great privilege they had!
Job had been questioning the justice of the treatment he was receiving from God. The LORD now came to question him, to show how foolish he had been. The LORD didn't explain the reason why Job had been treated in this way, but instead made Job realise that God is able to do everything such is His immeasurable wisdom, might and power.
By showing, in contrast, how powerless, ignorant and incompetent Job was, he would become convinced how impossible it was for him to form a correct judgement of God's actions.
This speech was made by the Creator himself. In it He made statements which haven't been disproved by men throughout the centuries, no matter how advanced in history and science. There are no other answers to the questions He asked: scientists may have discovered some of the processes at work, but are unable to explain the primary cause, if they are too proud to admit it comes from God.
1 Then the LORD answered Job out of the whirlwind, and said:
2 "Who is this who darkens counsel By words without knowledge?
3 Now prepare yourself like a man; I will question you, and you shall answer Me.