Fourth Part: On the Vices and Sins Opposed to Faith

733. Questions to be treated. - Under the name of an opposed sin there does not come a mere omission of the act of a precept, whether interior or of faith, or exterior or of confession of faith; but a contrary act, a sin of commission. But several vices and sins are opposed to faith:

1. To interior faith itself there is directly opposed a) infidelity, which from certain circumstances is called b) heresy and apostasy;

2. To faith there are indirectly opposed those things which for oneself or for others include occasion and danger of losing faith, such as a) communication with infidels and heretics; b) cooperation in infidelity and heresy; c) writings against doctrine of faith and morals; d) internal admission or external proposition of doctrines which are dangerous for faith.

3. To exterior faith or confession of faith there is directly opposed blasphemy.