Francis I. Andersen, Job (Tyndale OT Commentary), 68:

Men seek an explanation of suffering in cause and effect. They look backwards for a connection between prior sin and present suffering. The Bible looks forwards in hope and seeks explanations, not so much in origins as in goals. The purpose of suffering is seen, not in its cause, but in its result. The man was born blind so that the works of God could be displayed in him (Jn. 9:3).

But sometimes good never seems to come out of evil. Men wait in vain. They find God’s slowness irksome. They lose heart, and often lose faith. The Bible commends God’s self-restraint. The outworkings of His justice through the long processes of history, which sometimes require spans of many centuries, are part of our existence in time. It is easier to see the hand of God in spectacular and immediate acts, and the sinner who is not instantly corrected is likely to despise God’s delay in executing justice as a sign that He is indifferent or even absent. We have to be as patient as God Himself to see the end result, or to go on living in faith without seeing it. In due season we shall reap, if we do not faint.