This chapter seems to be out of place before Job’s final monologue (in 29-31), leading to some important questions about who is speaking. The point is that humans can do many marvelous things, but that only God can know Wisdom encompasses the qualities of experience, knowledge, and good judgment. The Old Testament book of Proverbs, which sometimes invokes a Woman as the personification of Wisdom, is a collection of aphorisms and moral teachings. Along with other biblical passages, it teaches, "The fear of the....
Job is the last named speaker, but these words seem out of place in his mouth since he continues his pleas of innocence and laments about his condition in the following three chapters. Chapter 28 seems to suggest an attitude of acceptance of the fact that humans can never penetrate the mysteries of the universe that are accessible only to God. In the book, however, Job is not yet at that point.
It may be that the chapter is an interlude inserted by the writer or later editor of the book to bring relief from the persistent questioning in the dialogues between Job and his friends. It is a way to begin to move away from what went before and give the reader a hint of what will come when God finally speaks. If this is true, it is meant as an aside to the reader (to us) and is not directly part of the conversation between Job and his friends.
The chapter does not denigrate human wisdom. There are many things that humans can discover by using the minds and ingenuity that God gave them. An example is given in the metaphor of mining, digging into the earth to find what had never before been seen, even by birds and animals (verses 1-11). Humans have brought hidden things to light (verse 11b). There are limits, however, and human beings are wise to accept them and admit that only God knows the way to wisdom.