Every judgement of conscience, be it right or wrong, be it about things evil in themselves or morally indifferent, is obligatory, in such wise that he who acts against his conscience always sins.

Clearly the person who accepts the Church as an infallible guide will believe whatever the Church teaches.

Humility is the mark of a genuine disciple.

It is altogether unlawful to kill oneself... Wherefore suicide is contrary to the inclination of nature, and to charity whereby every man should love himself... Life is God's gift to man, and is subject to His power, Who kills and makes to live. Hence whoever takes his own life, sins against God... for it belongs to God alone to pronounce sentence of death and life.

It would seem that the ingratitude, whereby a subsequent sin causes the return of sins previously forgiven, is a special sin. For, the giving of thanks belongs to counter passion, which is a necessary condition of justice. But justice is a special virtue. Therefore this ingratitude is a special sin. Thanksgiving is a special virtue. But ingratitude is opposed to thanksgiving. Therefore ingratitude is a special sin.

A man should remind himself that an object of faith is not scientifically demonstrable, lest presuming to demonstrate what is of faith, he should produce inconclusive reasons and offer occasion for unbelievers to scoff at a faith based on such ground.

Wonder is the desire of knowledge.