The hour when you say, "What does my happiness matter? It is poverty and filth, and a wretched complacency. Yet my happiness should justify existence itself!
There is no tomorrow to remember if we don’t do something today, and to live most fully today, we must do that which is of greatest importance. Let us not procrastinate those things which matter most.
A maxim is a conclusion upon observation of matters of fact, and is merely speculative; a "principle" carries knowledge within itself, and is prospective.
In other words, a person who is fanatic in matters of religion, and clings to certain ideas about the nature of God and the universe, becomes a person who has no faith at all.
What is held by the whole Church, and that not as instituted by Councils, but as a matter of invariable custom, is rightly held to have been handed down by authority.