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. For Matthew, Joseph was just because he followed the Law of God. He was a pious Jew who followed the Law, which meant he gave God his due. The Law of Moses was binding upon all Jews. However, following God's law, revealed through Moses, was not meant to be a mindless act.