Job Chapter 40 is divided into three sections. In Section 1, God addresses Job, asking him a question. 

Job 40:1-2

Moreover the Lord answered Job, and said, Shall he that contendeth with the Almighty instruct him? he that reproveth God, let him answer it.

The Lord establishes his almighty power. This is in parallel to the introduction of Chapter 38.

Job 38:1-7

Then the Lord answered Job out of the whirlwind, and said, Who is this that darkeneth counsel by words without knowledge? Gird up now thy loins like a man; for I will demand of thee, and answer thou me. Where wast thou when I laid the foundations of the earth? declare, if thou hast understanding. Who hath laid the measures thereof, if thou knowest? or who hath stretched the line upon it? Whereupon are the foundations thereof fastened? or who laid the corner stone thereof; When the morning stars sang together, and all the sons of God shouted for joy?

One distinct purpose of the Holy Bible is to teach and testify of the divinity of Christ. He is always at center stage. It is Christ who created the world. It is Christ who gave Moses the Ten Commandments. Jehovah of the Old Testament is Jesus Christ of the New Testament. Some Biblical scholars have identified over 250 names and titles and nearly 700 references to Christ in the Bible. It is summed up in the superlative phrase—"The Great I Am.” One cannot overlook the fact that the primary character of Job is not Job himself. It is Jesus Christ. Job represents the suffering of man. In that he has become our model and our teacher; however, even in the worst kind of suffering, we cannot equal the suffering of Christ. Christ suffered above all that humanity collectively has suffered. Christ suffered in the wilderness. Christ suffered in Gethsemane. Christ suffered during the trial. And Christ suffered on the Cross. He alone overcame all suffering, all trials, and all temptations without ever giving in to temptation. That is what qualified him to open the book, to become our Savior and our Redeemer, and to atone for our sins. 

At first it appears that the Lord is harsh on Job. After all Job has already suffered more than most of us suffer in a lifetime. He endured it remarkable well. However, far from being harsh, the Lord is teaching us through the story of Job that regardless of what we suffer, regardless of what trials we endure, we cannot equal Christ. We are still unworthy. We cannot through our suffering atone for our own sins. Only through the blood of the lamb and faith in Jesus Christ can we be saved. If we don’t understand that, then we do not understand the mission of the Savior. We don’t understand the atonement. We don’t understand mercy and grace. We don’t understand justice. We don’t understand God.

Job illustrates his humility before God by his inspiring answer. 

Job 40:3-5

Then Job answered the Lord, and said, Behold, I am vile; what shall I answer thee? I will lay mine hand upon my mouth. Once have I spoken; but I will not answer: yea, twice; but I will proceed no further.

The Lord is testing Job, and he passes the test. Notice, in the Lord’s answer to Job, the repetition of the command, “Gird up thy loins now like a man.” The Lord is not putting Job down. The Lord is lifting Job up to a higher plane than he has ever been. The sanctification of Job is the greater story. Job is being purified through his trials, and the Lord is commanding him to “Gird up thy loins now like a man.” There is a great word that captures the moment: “excelsior.” It means ‘higher’ or ‘ever upward.’ Job, in his despair, is asked to not give in to his grief but to strive harder, to transcend the natural man, and to seek for excellence. The Lord is telling Job that he must endure his trials and become sanctified.