I cannot sufficiently be astonished that such is the insanity of some men, such the impiety of their blinded understanding, such, finally, their lust after error, that they will not be content with the rule of faith delivered once and for all from antiquity, but must daily seek after something new, and even newer still, and are always longing to add something to religion, or to change it, or to subtract from it!

Avoid the profane novelty of words, St. Paul says (I Timothy 6:20) ... For if novelty is to be avoided, antiquity is to be held tight to; and if novelty is profane, antiquity is sacred.

I cannot sufficiently be astonished that such is the insanity of some men, such the impiety of their blinded understanding, such, finally, their lust after error, that they will not be content with the rule of faith delivered once and for all from antiquity, but must daily seek after something new, and even newer still, and are always longing to add something to religion, or to change it, or to subtract from it!

True piety admits no other rule than that whatsoever things have been faithfully received from our fathers the same are to be faithfully consigned to our children; and that it is our duty, not to lead religion whither we would, but rather to follow religion whither it leads; and that it is the part of Christian modesty and gravity not to hand down our own beliefs or observances to those who come after us, but to preserve and keep what we have received from those who went before us.

What, then, shall a Catholic Christian do ... if some novel contagion attempt to infect no longer a small part of the Church alone but the whole Church alike? He shall then see to it that he cleave unto antiquity, which is now utterly incapable of being seduced by any craft or novelty.

All novelty in faith is a sure mark of heresy.