20 This impious and foolish war is waged and sometimes supported by those who should be the first to come to Our aid. The errors appear in many forms and the enticements of vice wear different dresses. Both cause many even among our own ranks to be ensnared, seducing them by the appearance of novelty and doctrine, or the illusion that the Church will accept the maxims of the age. Venerable Brethren, you are well aware that we must vigorously resist and repel the enemy's attacks with the very weapons Borromeo used in his day.
Source: Editae Saepe (Vatican.va)