The long and bitter conflict between Job and his friends finally reaches a moment of profound reconciliation and atonement. Following the divine command, the friends offer the required sacrifices and approach Job to ask for his forgiveness. In response to their request, Job prays on their behalf [ביאור שטיינזלץ]. Because of this prayer, God shows favor to Job, accepting his plea and forgiving the friends for their misdeeds [רש״י, מצודת דוד].
This moment of divine pardon is deeply rooted in Job's personal greatness. Even though his friends had caused him tremendous pain and mocked him throughout his suffering, he still chooses to forgive them and pray for their well-being. This specific act of human forgiveness carries immense spiritual power. When a righteous person in this physical world finds merit in others and advocates for them, it actively silences any harsh accusations in the heavenly court. By choosing grace over bitterness, Job cancels the spiritual case against his friends, prompting God to completely wipe away their sins [חומת אנך].