Eliphaz to Job: "Call out now; Is there anyone who will answer you? And to which of the holy ones will you turn?" (Job 5:1)
Job's response: "how can a man be righteous before God? If one wished to contend with Him, He could not answer Him one time out of a thousand." (9:1)... "For He is not a man, as I am, That I may answer Him, And that we should go to court together. Nor is there any mediator between us, Who may lay his hand on us both." (v 32-33)
Job gets right to the heart problem very succinctly. Man cannot be reconciled to God; nor God to man without an appropriate mediator. Man cannot do this. Man cannot contend, or argue with God. Nor can man act as a mediator.
But, there is One who is a Mediator between both - "For there is one God and one Mediator between God and men, the Man Christ Jesus." (1 Tim. 2:5)
To answer Job's question: "how can a man be righteous before God?" Justification requires the work of the God-man, Jesus.
Only Christ is both God and Man - and able to "lay His hand on both."
We cannot answer God; another man cannot be the arbiter between He & us; it required Christ the God-man.
There is only one Mediator the text says. There is no other.