Pope Leo XIII, Humanum Genus
If those who are admitted as members are not commanded to abjure by any form of words the Catholic doctrines, this omission, so far from being adverse to the designs of the Freemasons, is more useful for their purposes. First, in this way they easily deceive the simple-minded and the heedless, and can induce a far greater number to become members. Again, as all who offer themselves are received whatever may be their form of religion, they thereby teach the great error of this age-that a regard for religion should be held as an indifferent matter, and that all religions are alike. This manner of reasoning is calculated to bring about the ruin of all forms of religion, and especially of the Catholic religion, which, as it is the only one that is true, cannot, without great injustice, be regarded as merely equal to other religions.