Vision possesses such lofty importance because the eyes are the windows to the "soul of the soul." A blemish to the sense of vision, when the eyes gaze upon some forbidden image, is grave indeed, as stressed by the verse in the Book of Eichah, "My eye affects my soul because of all the daughters of the city" (Eichah, 3:51). This means that what a man sees can cause him to lose a portion of his holiness.