New revelations regarding faith or morals ... have always been abhorred and challenged in the Church ... Hence, the Sovereign Pontiffs, the Councils, and the Fathers have been most careful to reject all novelties or new doctrines on matters of faith which differed from those already received.
Alphonsus LiguoriHe would be guilty of mortal sin, because he exposes himself to the danger of grievously offending God. Hence, before he acts he must lay aside the doubt; and if he has not hitherto done so, he must confess it, at least, as it is before God. But the scrupulous, who have doubts about everything, must follow another rule: they must obey their confessor. When he tells them to conquer their doubts, and to act against scruples, they should obey with exactness; otherwise they will render themselves unable and unfit to perform any spiritual exercise.
Alphonsus LiguoriSaint Teresa, as the Roman Rota attests, never fell into any mortal sin; but still Our Lord showed her the place prepared for her in Hell; not because she deserved Hell, but because, had she not risen from the state of lukewarmness in which she lived, she would in the end have lost the grace of God and been damned.
Alphonsus LiguoriTo put into practice the teachings of our holy faith, it is not enough to convince ourselves that they are true; we must love them. Love united to faith makes us practice our religion.
Alphonsus Liguori