Basic Facts That Catholics Must Know to be saved

Feb 27, 2025

The Glossary of Terms and Principles

This glossary contains important definitions of key terms and principles about the Catholic Faith, about the post-Vatican II “Church,” about how the Catholic Church views non-Catholic religions, etc. which people should see. It explains such terms as “Magisterium,” the Church’s indefectibility, “ecumenism,” “sedevacantism,” “Papacy,” “Papal Infallibility,” “heretic,” “antipope,” “Novus Ordo,” and others.

Since very few still have the faith and even fewer preach it, there is a widespread ignorance of even the basic truths of the Catholic Faith in our day.

Pope Benedict XIV, Cum Religiosi (# 4), June 26, 1754: “See to it that every minister performs carefully the measures laid down by the holy Council of Trent… that confessors should perform this part of their duty whenever anyone stands at their tribunal who does not know what he must by necessity of means know to be saved…”

We will now review some of them:

The Trinity and the Incarnation

There is one God in Three Divine Persons (Father, Son and Holy Ghost). The Father is God, the Son is God, and the Holy Ghost is God; yet they are not three gods, but One God. The Second Person of the Blessed Trinity, the Son of God, assumed a human nature and became man from the flesh of the Virgin Mary. Our Lord Jesus Christ is one Divine Person with two natures: divine and human. He is God and man. The Trinity (One God: Father, Son and Holy Ghost) and the Incarnation are the two most essential mysteries of the Catholic Faith which no one above reason can be ignorant of and be saved.

St. Thomas Aquinas, Summa Theologica: “After grace had been revealed, both the learned and simple folk are bound to explicit faith in the mysteries of Christ, chiefly as regards those which are observed throughout the Church, and publicly proclaimed, such as the articles which refer to the Incarnation, of which we have spoken above.”

Saint Thomas Aquinas, Summa Theologica: “And consequently, when once grace had been revealed, all were bound to explicit faith in the mystery of the Trinity.”

All who die in mortal sin will go to Hell

Pope Eugene IV, Council of Florence, “Letentur coeli,” Sess. 6, July 6, 1439, ex cathedra: “We define also that… the souls of those who depart this life in actual mortal sin, or in original sin alone, go straightaway to Hell, but to undergo punishments of different kinds.”

Catholics must also know that all who die in mortal sin will go to Hell forever. Mortal sins include: murder, fornication (i.e. sexual acts outside of marriage or acts leading up to sex outside of marriage), lying, drunkenness, consenting to impure thoughts, masturbation, looking at pornography, adultery, cheating, taking God’s name in vain, birth control (NFP) or artificial contraception, assisting the propagation of heresy, funding heretics, dishonoring the Sabbath, breaking the commandments, etc. If someone were to commit a mortal sin and then go to Confession, he must have the firm resolution never to commit the sin again. This is called the firm purpose of amendment. If a person commits a mortal sin and doesn’t have the firm purpose of amendment when he goes to Confession, he commits a sacrilege and the Confession is invalid. Most souls go to Hell because of sins of the flesh. Those who are committing sins of the flesh need to stop immediately if they don’t want to perish forever in the fires of Hell.

St. Alphonsus on the damnation of the impure: “Continue, O fool, says St. Peter Damian (speaking to the unchaste), continue to gratify the flesh; for the day will come in which thy impurities will become as pitch in thy entrails, to increase and aggravate the torments of the flame which will burn thee in Hell: ‘The day will come, yea rather the night, when thy lust shall be turned into pitch, to feed in thy bowels the everlasting fire.” (Preparation for Death, abridged version, p. 117)