I believe that we may interpret the voices of the four friends, as trains of thought personified, which run through Job's mind during this period of utter darkness, as human understanding and the accuser's arrows are pitted against the light which he had previously received, if we consider the following: he claims that he is deserted by family and friends 16.7; 19.13; he is in a place of isolation and shame, where those with infectious diseases dwell, and it seems unlikely to me that his 'friends' would take a risk in entering such a place, showing such loyalty, the reality being, that when calamity strikes, friends are most often, nowhere to be seen; and also because one of the distinguishing marks of being in the 'dark night' is that one finds onself deserted by all, as the presence of friends would have given a degree of comfort, despite their differing theologies.
The depth of suffering can be appreciated with more clarity, moreover, if one considers that Job goes through a trial of extreme confusion with the contest taking place in his mind and which enables us to identify with it more easily in a similar trial.
There is also the matter of the style of the speeches, where there is no direct communication, the reasoning going round and round in circles and often called wind 8.2; 15.2; 16.3, and which is confirmed when God speaks out of the whirlwind 38.1 denoting confusion. Gutiérrez describes it helpfully as ' the arguments are like a wheel spinning in the air.'
Job is taunted throughout the speeches, by two thoughts, the first of which has been the temptation of the enemy since the beginning: Did God say? Genesis 3.1. God had declared Job sinless, and the accuser desired that Job would doubt it, losing his testimony. The voices taunted him with the thought that if indeed he was sinless, then God would have no reason to withdraw. If Job admitted he was not, then God would restore him as he desired. The issue was over Job's righteousness, and what is special about Job, is that he brings illumination to the severest of trial in the spiritual realm with which Jesus himself also had to contend, that is the seeming desertion of God in the hour of need of his most devout servants.
In this crucible, the words of the sufferer seem beyond comprehension, being so exaggerated and dramatic. We find the same also with Jeremiah, David, and Christian mystics. Job responds with increasing confusion until he reaches the depth of despair.
Finally, we see the curtain drawn back as God returns and speaks, as we are given a glimpse of the administration of the heavenly and earthly realms, where love and freedom rules, and not might, as we are shown the freedom that God gives his creation, and which has been denied to him by the demands made by Job in his grief.
Job finally understands the purpose of the silence for himself and also for those who are willing to do all things without murmuring and arguing so that you may be blameless and innocent children of God without blemish, Phil. 2.14-15.
Job is convicted and repents of his lamentation of the loss of God's presence (in dust and ashes) and has at last understood that he must walk by faith in the light already given. Even enjoyment of the presence of God must be given up willingly to worship the giver of the gift and not the gift itself. He is validated in that he had spoken correctly about God, that the trial was not because he sinned, and the accuser(s) were wrong. Finally, 'Job reflects the gratitious love of God' as P. H. Jones puts it, wanting nothing for himself, happy to allow God to grace with his presence at his choosing, and willing to walk by faith alone, in unquestioning loyalty. Job's maturity is complete.