stance, and, refusing
to mend their pernicious and deadly doctrines, persist in defending
them." Now pernicious and deadly doctrines are none but those which
are contrary to the dogmas of faith, whereby "the just man liveth"
(Rom. 1:17). Therefore heresy is about matters of faith, as about its
proper matter.

_I answer that,_ We are speaking of heresy now as denoting a
corruption of the Christian faith. Now it does not imply a corruption
of the Christian faith, if a man has a false opinion in matters that
are not of faith, for instance, in questions of geometry and so
forth, which cannot belong to the faith by any means; but only when a
person has a false opinion about things belonging to the faith.

Now a thing may be of the faith in two ways, as stated above (I, Q.
32, A. 4; I-II, Q. 1, A. 6, ad 1; I-II, Q. 2, A. 5), in one way,
directly and principally, e.g. the articles of faith; in another way,
indirectly and secondarily, e.g. those matters, the denial of which
leads to the corruption of some article of faith; and there may be
heresy in either way, even as there can be faith.

Reply Obj. 1: Just as the heresies of the Jews and Pharisees were
about opinions relating to Judaism or Pharisaism, so also heresies
among Christians are about matter touching the Christian faith.

Reply Obj. 2: A man is said to expound Holy Writ in another sense
than that required by the Holy Ghost, when he so distorts the meaning
of Holy Writ, that it is contrary to what the Holy Ghost has
revealed. Hence it is written (Ezech. 13:6) about the false prophets:
"They have persisted to confirm what they have said," viz. by false
interpretations of Scripture. Moreover a man professes his faith by
the words that he utters, since confession is an act of faith, as
stated above (Q. 3, A. 1). Wherefore inordinate words about matters
of faith may lead to corruption of the faith; and hence it is that
Pope Leo says in a letter to Proterius, Bishop of Alexandria: "The
enemies of Christ's cross lie in wait for our every deed and word, so
that, if we but give them the slightest pretext, they may accuse us
mendaciously of agreeing with Nestorius."

Reply Obj. 3: As Augustine says (Ep. xliii) and we find it stated
in the Decretals (xxiv, qu. 3, can. Dixit Apostolus): "By no means
should we accuse of heresy those who, however false and perverse
their opinion may be, defend it without obstinate fervor, and seek
the truth with careful anxiety, ready to me