Catholics lose their faith by their sins, and chiefly by the sin of pride. All heretics and apostates show this in their conduct and in their words. They adhere to their own opinions and refuse to submit to the divine teaching of the church. O dear brethren! let us fear this sin of pride more than all other sin--a temptation, too, that is very apt to come up when we are ridiculed by unbelievers for our faith. Then is the time to confess the truth boldly, for if we deny our Lord before men he will deny us before the face of his Father in heaven. Let us keep our faith by purity of life and humility of heart; for, as says the _Imitation of Christ:_ "What doth it avail thee to discourse profoundly of the Trinity, if thou be wanting in humility, and consequently displeasing to the Trinity? If thou didst know the whole Bible by heart, and the sayings of all the philosophers, what would it profit thee without the love of God and his grace?" ------------------- {282} Sermon LXXXIII. _In the name of the Father, and of the Son, and of the Holy Ghost._ --St. Matthew xxviii. 19. To-day, my dear brethren, the church celebrates the greatest of all the mysteries of our religion: the mystery of the Holy Trinity; of the one God in three Divine Persons--the Father, the Son, and the Holy Ghost. We all believe it; we must believe it if we would be saved. But no one of us can perfectly understand it. St. Patrick, you know, is said to have illustrated it to his converts by showing them the shamrock with its three leaves on one stem; but, of course, he never pretended that this was a perfect explanation of it. No perfect explanation of it can be given to us. And why not? Is it because it really has no explanation? No, but because we are not able to understand the one which might be given. Explain the solar system to a child of five years: will he understand you? It is something the same with us and this greater mystery of God. Some people, especially at the present day, who consider themselves very wise, say to themselves and to others: "Oh! this doctrine of the Trinity cannot be true." Ask them why not, and they will say: "Because we cannot understand it; it seems to us to be nonsense." Well, what does their argument amount to? Just to this: "If the doctrine were true we should understand it; but we don't understand it, therefore it is not true." {283} "If it were true," they say, "we should understand it." And why? "Why, of course, because we are so wise that we can understand everything. It is well enough for stupid people, like those benighted Romanists, to believe what they don't understand, but such a proceeding would be quite below our dignity and intelligence. It is quite absurd to suppose that there is any mystery so deep that we cannot see to the bottom of it."