Then Job answered the Lord and said:
“I know that you can do all things,
and that no purpose of yours can be thwarted.
What Job thought he wanted from God, and what he eventually acknowledged about God could be no more different. All throughout the story, as Job theologically jousts with his friends, he wants most for God to vindicate him -- to explain his pain and to focus clearly on Job the man. But when God does finally enter the circle of theological discussion, at the end of God's questioning of Job's lack of power, Job can only worship and repent.
Job does so by acknowledging that God is sovereign and wise in His purposes. Inherent in that humble admission is that Job's own experiences were part of the wise purposes of a holy God. Job repents because he had questioned God's purposes to some degree as he focused on himself. Now that he is thinking clearly about God again, he must admit that God is in control and has been all along. The wisdom of God prevails over all of Job's questions.
The main point that God makes to Job that leads him to this confession is that God is clearly in control of all the natural world. Job was powerless to change the weather, to understand the workings of the animal kingdom, or to control the wildness of any beast. Yet God made and controlled them all with authority. If God controlled the fiercest behemoth and leviathan, then nothing that Job faced was outside of God's wise care.
God can do all things. This means that nothing escapes His control. It is a belief in the sovereign power of God at work in all the universe that Job comes to claim. And that truth brings Job back around in worship and repentance. God's purposes cannot be stopped. God has no true enemies that can prevail against Him. Nothing truly fights His will. No plan of His can be successfully challenged. God's purposes rule over all the universe... including the details of my life.