What does Deum de Deo lumen de lumine Deum verum de Deo vero mean?

"Deum de Deo, lumen de lumine, Deum verum de Deo vero" is a Latin phrase from the Nicene Creed, a statement of Christian faith. It translates to "God from God, Light from Light, true God from true God." This phrase emphasizes the divine nature and origin of Jesus Christ as being of the same substance as God the Father.