The grace of all virtues comes from God. But the cardinal, or hinge, virtues are those that we have to work at developing in order to fully receive their graces. In other words, the virtues take practice. Justice, giving others what they deserve, takes practice. It also takes prudence, the first of the cardinal virtues.
Justice flows directly out of prudence.
Prudence tells us the right thing to do in a particular circumstance. Prudence gives us the truth, God shows us the way, and we act. Justice is doing that right thing. Justice comes from a Latin word, justus , meaning lawful, just, righteous. In the Scriptures, we find several people who are called just and righteous.