Isaiah 34:15

Hence it is rightly said through the prophet, under the similitude of Judah, to the soul that sins and excuses itself, "There the urchin had her nest." For by the name of urchin is denoted the duplicity of a mind that is insincere, and cunningly defends itself; because, to wit, when an urchin is caught, its head is perceived, and its feet appear, and its whole body is exposed to view; but no sooner has it been caught than it gathers itself into a ball, draws in its feet, hides its head, and all is lost together within the hands of him that holds it which before was all visible together. So assuredly, so insincere minds are, when they are seized hold of in their transgressions. For the head of the urchin is perceived, because it appears from what beginning the sinner has advanced to his crime; the feet of the urchin are seen, because it is discovered by what steps the iniquity has been perpetrated; and yet by suddenly adducing excuses the insincere mind gathers in its feet, in that it hides all traces of its iniquity; it draws in the head, because by strange defences it makes out that it has not even begun any evil; and it remains as it were a ball in the hand of one that holds it, because one that takes it to task, suddenly losing all that he had just now come to the knowledge of, holds the sinner rolled up within his own consciousness, and, though he had seen the whole of him when he was caught, yet, illuded by the tergiversation of dishonest defence, he is in like measure ignorant of the whole of him. Thus the urchin has her nest in the reprobate, because the duplicity of a crafty mind, gathering itself up within itself, hides itself in the darkness of its self-defence.