From the essay, The Will, by William James:
Spinoza long ago wrote in his ethics that anything that a man can avoid under the notion that it is bad he may also avoid under the notion that something else is good. He who habitually acts sub specie mali, under the negative notion, the notion of the bad, is called a slave by Spinoza. To him who acts habitually under the notion of good he gives the name of freeman. See to it now, I beg you, that you make freemen of your pupils by habituating them to act, whenever possible, under the notion of a good. Get them habitually to tell the truth, not so much through showing them the wickedness of lying as by arousing their enthusiasm for honor and veracity.
Found in, The Heart of William James,
William James (Author), Robert D. Richardson (Editor).
(This book is filled with good stuff and is Highly Recommended. )
Also available here: Talks to Teachers, William James, via Project Gutenberg: http://www.gutenberg.org/ebooks/16287
From The Ethics, Benedictus de Spinoza:
PROP. LXVII. A free man thinks of death least of all things; and his wisdom is a meditation not of death but of life.
Proof.–A free man is one who lives under the guidance of reason, who is not led by fear (IV. lxiii.), but who directly desires that which is good (IV. lxiii. Coroll.), in other words (IV. xxiv.), who strives to act, to live, and to preserve his being on the basis of seeking his own true advantage; wherefore such an one thinks of nothing less than of death, but his wisdom is a meditation of life. Q.E.D.
Ethics, Benedictus de Spinoza via Project Gutenberg