This quote is taken from Measure for Measure, a play by William Shakespeare, written in 1603 or 1604. In act 3 scene 1 a dialog between Duke Vincentio says to Isabella "Virtue is bold, and goodness never fearful. Have you not heard speak of Mariana, the sister of Frederick the great soldier who miscarried at sea?" It means those who are virtuous and approach things with good intent are never afraid, they are driven by their goodness and thus overcome their fears. In context Duke Vincentio is replying to Isabella "Let me hear you speak farther. I have spirit to do anything that appears not foul in the truth of my spirit."
