Article III. On dangers of faith

521. Preliminary note. Since faith is so necessary for obtaining salvation, it follows at once that man is bound with all diligence to avoid the proximate dangers of faith. Such dangers are either internal, e.g. pride, cupidity, an unregulated life; or external, of which the principal are: 1. association or communication with heretics and unbelievers, 2. attendance at non-Catholic schools, 3. reading of bad books, 4. marriages entered with heretics or unbelievers. About each we shall say a few things. By way of scholion we shall treat of the internal dangers of faith.