The Roman Catholic Church has offered the most persistent opposition to Freemasonry. The Church has prohibited its members from being Freemasons since 1738. Since then the Church made it clear that membership in Masonic associations will lead to excommunication.
The Catholic Church accuses that the Free Masons incorporate Deism and Naturalism as part of their masonic beliefs. Both of these philosophies have been condemned by the Church as atheistic.
After the Second Vatican Council many thought that the Church was going soft on Free Masonry. But the Church position was reiterated by the then Cardinal Joseph Ratzinger in 1983. Joseph Cardinal Ratzinger being the prefect of the Congregation for the Doctrine of the Faith, with the apostolic approval of Pope John Paul II, issued a Declaration on Masonic Associations, which reiterated the Church's objections to Freemasonry. The Declaration states: "The faithful who enroll in Masonic associations are in a state of grave sin and may not receive Holy Communion...." and "...the Church’s negative judgment in regard to Masonic association(s) remains unchanged since their principles have always been considered irreconcilable with the doctrine of the Church and therefore membership in them remains forbidden."
Many Catholics believe that the prophecy in revelation about the second beast (Revelation 13:11) is made about the Free Masons. But the Church has never openly made any such claims.