According to the first article of the Justinian Code, Justice is

Answer: Wishing to pay back any kind of debt.

Explanation:

Justice was considered as a perpetual wish for fairness and law respecting.

The most important laws of the first article of Justinian's code are honesty, giving duty and not wanting to hurt anyone. Justice is the Justinian's code impact that's been lasting since then and we can find justice in today's law with many other Justinian's ideas.

These laws are very powerful and well connected.