Voltaire, Treatise on Toleration
https://archive.org/stream/tolerationother00volt#page/86/mode/2up

I am very far from opposing the maxim, "outside the church there is no salvation;" I respect it and all that it teaches, but, after all, do we know all the ways of God, and all the extent of his mercy? Are we not permitted to hope in him, as well as to fear him? Is it not sufficient if we are faithful to the Church? Must every individual usurp the rights of Divinity and determine, before it, the eternal fate of all men?

When we wear mourning for a king of Sweden, Denmark, England or Prussia, do we say that we are in mourning for a damned soul that is burning eternally in hell? There are about forty millions of inhabitants in Europe who are not members of the Church of Rome; should we say to every one of them, "Sir, since you are infallibly damned, I shall neither eat, converse, nor have any connections with you?"

Is there an ambassador of France who, when he is presented to the Grand Seigneur for an audience, will seriously say to himself, his highness will infallibly burn for all eternity for having submitted to circuмcision? If he really thought that the Grand Seigneur was a mortal enemy of God, and the object of his vengeance, could he converse with such a person; ought he to be sent to him? With what man could we carry on any commerce, or perform any of the civil duties of society, if we were indeed convinced that we were conversing with persons destined to eternal damnation?

O different worshippers of a peaceful God! if you have a cruel heart, if, while you adore he whose whole law consists of these few words, "Love God and your neighbor," you have burdened that pure and holy law with false and unintelligible disputes, if you have lighted the flames of discord sometimes for a new word, and sometimes for a single letter of the alphabet; if you have attached eternal punishment to the omission of a few words, or of certain ceremonies which other people cannot comprehend, I must say to you with tears of compassion for mankind: "Transport yourselves with me to the day on which all men will be judged and on which God will do unto each according to his works.

"I see all the dead of past ages and of our own appearing in his presence. Are you very sure that our Creator and Father will say to the wise and virtuous Confucius, to the legislator Solon, to Pythagoras, Zaleucus, Socrates, Plato, the divine Antonins, the good Trajan, to Titus, the delights of mankind, to Epictetus, and to many others, models of men: Go, monsters, go and suffer torments that are infinite in intensity and duration. Let your punishment be eternal as I am. But you, my beloved ones, John Châtel, Ravaillac, Damiens, Cartouche, etc. who have died according to the prescribed rules, sit forever at my right hand and share my empire and my felicity."

You draw back with horror at these words; and after they have escaped me, I have nothing more to say to you.

A "traditionalist" priest once plagiarized almost word for word the arguments of Rousseau and Voltaire in an attempt to try and convince me that Fr. Leonard Feeney and the supporters of the St. Benedict Center are extremists and heretics.

All traditionalists acknowledge that Fɾҽҽmαsσɳɾყ has been seeking to destroy the Church for the last few centuries, but very few have realized that their strategy involved first and foremost the undermining of the dogma no salvation outside the Church. This one dogma has been on their radar for a long time.