24 What, therefore, sect of the Freemasons is, and what course it pursues, appears sufficiently from the summary We have briefly given. Their chief dogmas are so greatly and manifestly at variance with reason that nothing can be more perverse. To wish to destroy the religion and the Church which God Himself has established, and whose perpetuity He insures by His protection, and to bring back after a lapse of eighteen centuries the manners and customs of the pagans, is signal folly and audacious impiety. Neither is it less horrible nor more tolerable that they should repudiate the benefits which Jesus Christ so mercifully obtained, not only for individuals, but also for the family and for civil society, benefits which, even according to the judgment and testimony of enemies of Christianity, are very great. In this insane and wicked endeavor we may almost see the implacable hatred and spirit of revenge with which Satan himself is inflamed against Jesus Christ. - So also the studious endeavour of the Freemasons to destroy the chief foundations of justice and honesty, and to co-operate with those who would wish, as if they were mere animals, to do what they please, tends only to the ignominious and disgraceful ruin of the human race. The evil, too, is increased by the dangers which threaten both domestic and civil society. As We have elsewhere shown,(14) in marriage, according to the belief of almost every nation, there is something sacred and religious; and the law of God has determined that marriages shall not be dissolved. If they are deprived of their sacred character, and made dissoluble, trouble and confusion in the family will be the result, the wife being deprived of her dignity and the children left without protection as to their interests and well being.-To have in public matters no care for religion, and in the arrangement and administration of civil affairs to have no more regard for God than if He did not exist, is a rashness unknown to the very pagans; for in their heart and soul the notion of a divinity and the need of public religion were so firmly fixed that they would have thought it easier to have city without foundation than a city without God. Human society, indeed for which by nature we are formed, has been constituted by God the Author of nature; and from Him, as from their principle and source, flow in all their strength and permanence the countless benefits with which society abounds. As we are each of us admonished by the very voice of nature to worship God in piety and holiness, as the Giver unto us of life and of all that is good therein, so also and for the same reason, nations and States are bound to worship Him; and therefore it is clear that those who would absolve society from all religious duty act not only unjustly but also with ignorance and folly.
Source: Humanum Genus (Vatican.va)