Saint Thomas Aquinas

Beware the man of one book.
Saint Thomas Aquinas - Two Precepts of Charity
Three things are necessary for the salvation of man: to know what he ought to believe; to know what he ought to desire; and to know what he ought to do.

Beware the man of one book.

He who is dying of hunger must be fed rather than taught.

Perfection of moral virtue does not wholly take away the passions, but regulates them.

- Saint Thomas Aquinas