# How do you recognize a heretic?

**URL:** <https://forum.catholictalk.net/t/how-do-you-recognize-a-heretic/4253>\
**Category:** Apologetics\
**Created:** [September 29, 2026, 9:20pm UTC](https://forum.catholictalk.net/t/how-do-you-recognize-a-heretic/4253 "2026-09-29T21:20:52Z")\
**Posts on this page:** 1\
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**Author:** ![immutable\_catholic](https://avatars.discourse-cdn.com/v4/letter/i/9e8a1a/32.png) [@immutable\_catholic](https://forum.catholictalk.net/u/immutable_catholic)\
**Post date:** [September 29, 2026, 9:20pm UTC](https://forum.catholictalk.net/t/how-do-you-recognize-a-heretic/4253/1 "2026-09-29T21:20:52Z")

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The Saints give the body of Christ; the Catholic church, some clues.

St. Thomas Aquinas, Summa Theologica, Pt. I-II, Q. 103, A. 4: “All ceremonies are professions of faith, in which the interior worship of God consists. _**Now man can make profession of his inward faith, (BY DEEDS AS WELL AS BY WORDS): and in either profession, if he make a false declaration, he sins mortally.**_”

St. Robert Bellarmine, De Romano Pontifice, II, 30: “… for men are not bound, or able to read hearts; _**but when they (SEE) that someone is a heretic by (HIS EXTERNAL WORKS),**_ they judge him to be a heretic pure and simple, and condemn him as a heretic.”

The Magisterium of the Catholic church has also given instructions to its laity, when they see heretic by word and deed. Its dogmatic because its taken from the infallible scriptures; Titus 3:10-11.

Titus 3:10-11 A man that is a heretic, after the first and second admonition, avoid:[](https://drbo.org/cgi-bin/d?b=drb&bk=63&ch=3&l=11-#x)Knowing that he, that is such an one, is subverted, and sinneth, being condemned _ **by his own judgment** _.