Right away Eliphaz accuses Job of sin and that this sin is the cause of his suffering.
Job 4:5-7 But now it is come upon thee, and thou faintest; it toucheth thee, and thou art troubled. 6 Is not this thy fear, thy confidence, thy hope, and the uprightness of thy ways? 7 Remember, I pray thee, who ever perished, being innocent? or where were the righteous cut off? (KJV)
but we know the righteous also are allowed to suffer at times as well. Assuming that troubles, sickness, persecution, etc. only come of sin is part of why later God is upset with Job's three friends. He is also saying that Job was not upright in his ways, perhaps self-righteous.
Yet God said:
Job 1:8 And the LORD said unto Satan, Hast thou considered my servant Job, that there is none like him in the earth, a perfect and an upright man, one that feareth God, and escheweth evil? (KJV)
Satan himself did argue the point with God:
Job 1:9 Then Satan answered the LORD, and said, Doth Job fear God for nought? (KJV)