The power and providence of God remain unchallenged. The first four verses we find Job asking rhetorical questions, because the answer to all of them would only be God. The descriptions that he then lays out refer to the power and providence of God which remain unchallenged.
He concludes by stating that all which he had just mentioned is but a small token of all that God is able to do and all that God has under His control. I love the thought that we just hear a very small whisper of the power and the providence of God. We just catch an imperfect and small glimpse of all that He is able to do. Job describes it as a whisper.
He continues on and asks the question: who is able to understand the thunder of His power. Did you notice the juxtaposition? He uses whisper to describe all that we know about God, which is very little, and uses thunder to describe the power and providence of God, which, by the way, remain unchallenged.