In Job 33:19 Elihu tells Job that his pain and suffering is a chastisement from God. What did Job do to cause God to put this sickness upon him to start with?
Elihu scolds Job for complaining that God has caused him to suffer without explaining why. "Why do you complain against Him that He does not give an account of all His doings?" (Job 33:13). There are times that God does explain, but people don't pay attention. "Indeed God speaks once, or twice, yet no one notices it. In a dream, a vision of the night, when sound sleep falls on men, while they slumber in their beds" (Job 33:14-15). But what God is doing through suffering is teaching men (Job 33:16), stopping them from doing wrong (Job 33:17), and keeping them from pride (Job 33:17) in order to keep them from death (Job 33:18). Elihu is not saying that any of these reasons are the ones that explain why Job is suffering, but that suffering can have good results in the lives of men from God's viewpoint.
"Man is also chastened with pain on his bed, and with unceasing complaint in his bones; so that his life loathes bread, and his soul favorite food. His flesh wastes away from sight, and his bones which were not seen stick out. Then his soul draws near to the pit, and his life to those who bring death" (Job 33:19-22).
Elihu is saying that a man may suffer greatly, even to the point of nearly dying. Again, Elihu is not saying that the man is Job, though Job is greatly suffering. Elihu is setting up an example for his next point: that the suffering is worth it, if it saves a man.
"If there is an angel as mediator for him, one out of a thousand, to remind a man what is right for him, then let him be gracious to him, and say, 'Deliver him from going down to the pit, I have found a ransom'; let his flesh become fresher than in youth, let him return to the days of his youthful vigor; then he will pray to God, and He will accept him, that he may see His face with joy, and He may restore His righteousness to man. He will sing to men and say, 'I have sinned and perverted what is right, and it is not proper for me. He has redeemed my soul from going to the pit, And my life shall see the light'" (Job 33:23-28).
Therefore, suffering is a tool used by God to save and teach men. "Behold, God does all these oftentimes with men, to bring back his soul from the pit, that he may be enlightened with the light of life" (Job 33:29-20). See Hebrews 12:5-14, which talks about this same subject.
Apparently Job draws breath to object, but Elihu tells him stay silent and listen because Elihu is trying bring Job back in line with righteousness (Job 33:31-33). He then proceeds to quote Job's arguments that were incorrect and proves where Job made his mistakes. A storm comes up while Elihu is speaking (Job 37) and God takes over proving to Job how little he understood (Job 38-39), which led to the question: "Then the LORD said to Job, 'Will the faultfinder contend with the Almighty? Let him who reproves God answer it'" (Job 40:1-2). Job admits he has no answer. "Then Job answered the LORD and said, 'Behold, I am insignificant; what can I reply to You? I lay my hand on my mouth. Once I have spoken, and I will not answer; even twice, and I will add nothing more'" (Job 40:3-5).
God continues to press His point and Job admits that he was wrong. "Then Job answered the LORD and said, "I know that You can do all things, and that no purpose of Yours can be thwarted. 'Who is this that hides counsel without knowledge?' Therefore I have declared that which I did not understand, things too wonderful for me, which I did not know. 'Hear, now, and I will speak; I will ask You, and You instruct me.' I have heard of You by the hearing of the ear; but now my eye sees You;
therefore I retract, and I repent in dust and ashes" (Job 42:1-6).
God then tells Job's friends that they misspoke when they accused Job of sinning. But read Job 42:7-9 carefully and notice that is the three friends. Elihu, the fourth to speak, is not among their number. That is because as a prophet of God, speaking God's words to Job, Elihu had not misspoken as Job and his three friends had done.