God credits righteousness as a gift to the person who believes, not to the person who faithfully works for it.
Catholics are busy developing within themselves the righteousness required to enter the kingdom of God.
Protestants are credited as a free gift the righteousness required to enter the kingdom of God the moment they believe. They're not working for it. They already have it.
Justified has two meanings in scripture. You don't become righteous by your words, you show yourself to be righteous (or not righteous) by your words.
Faith makes you righteous. What you do shows you to be righteous. And so a man is justified by, both, faith and works (James 2:24). His faith makes him righteous (Philippians 3:9). His works show him to have faith (James 2:18).