The things that we love tell us what we are.

Three conditions are necessary for Penance: contrition, which is sorrow for sin, together with a purpose of amendment; confession of sins without any omission; and satisfaction by means of good works.

We must love them both, those whose opinions we share and those whose opinions we reject, for both have labored in the search for truth, and both have helped us in finding it.

Practical sciences proceed by building up; theoretical science by resolving into components.

True peace consists in not separating ourselves from the will of God.

If... the motion of the earth were circular, it would be violent and contrary to nature, and could not be eternal, since ... nothing violent is eternal .... It follows, therefore, that the earth is not moved with a circular motion.

The magnitude of the punishment matches the magnitude of the sin. Now a sin that is against God is infinite; the higher the person against whom it is committed, the graver the sin-it is more criminal to strike a head of state than a private citizen-and God is of infinite greatness. Therefore an infinite punishment is deserved for a sin committed against Him.