An official title or public praise does not make someone just. Fair judgment requires hearing both sides, considering sound evidence, resisting personal favoritism, and possessing the knowledge and competence appropriate to the task.
For example, two people contest a piece of land. If the decision-maker hears only the powerful party, the other person’s right may be lost.
The phrase بَيْنَ النَّاسِ highlights the judge’s position between people whose competing rights require careful adjudication.