The book of Job is, first and foremost, presenting Job as a type of Jesus the suffering servant. Job is the perfect, upright man (Job 1-2), the exemplary righteous man (Ezek. 14), who speaks what is right (Job 42) as he wrestles with God seeking a resurrection-vindication.
And at the ninth hour Jesus cried with a loud voice, “Eloi, Eloi, lema sabachthani?” which means, “My God, my God, why have you forsaken me?” (Mark 15:34)
Just as the Psalms are firstly the songs of Jesus, but become the songs of the church; Job also secondarily becomes a guide for the righteous to wrestle with God through our suffering and the suffering of our brothers. But unlike Job, our great accuser has now been cast out of heaven. More than that, while Job ascends into God’s presence only at the end of his story, we have access to God immediately and continually through Jesus in whom we have already ascended.
For we do not have a high priest who is unable to sympathize with our weaknesses, but one who in every respect has been tempted as we are, yet without sin. Let us then with confidence draw near to the throne of grace, that we may receive mercy and find grace to help in time of need. (Hebrews 4:15-16)
More than that, as the church we reign together with him.
[God] raised us up with him and seated us with him in the heavenly places in Christ Jesus. (Ephesians 2:6)
Finally, the book of Job serves as a caution to us, a reminder that God calls his own son, and all who follow him, to temporary sufferings and deprivations of the privileges of sonship so that through our suffering he can achieve an even more glorious outcome. Here and now the redeemed do not deserve these sufferings, but just like the sufferings of Jesus, we endure them as soldiers on a mission to bring about a far greater good.
Jesus said to him, “Then the sons are free. However, not to give offense to them, go to the sea and cast a hook and take the first fish that comes up, and when you open its mouth you will find a shekel. Take that and give it to them for me and for yourself.” (Matthew 17:26-27)