Selected quotation
"If a plant cannot live according to its nature, it dies; and so a man."
~ Henry David Thoreau, "The Writings of Henry David Thoreau"
Various books with quotations, aphorisms and proverbs:
The Oxford Dictionary of Quotations
The Yale Book of Quotations
Oxymoronica: Paradoxical Wit & Wisdom From History's Greatest Wordsmiths
Doonesbury.com's The War in Quotes
The Ultimate Guide to the Perfect Word: Quotes - Titles - Poetry - Tips - Words
A Continual Feast: Words of Comfort and Celebration, Collected by Father Tim
The Proverbs Driven Life: Timeless Wisdom for Your Words, Work, Wealth, and Relationships
Positive Thinking Every Day: An Inspiration for Each Day of the Year
America's Popular Sayings: Over 1600 Expressions on Topics from Beauty to Money and Everything In Between
8,789 Words of Wisdom
365 Inspirational Quotes (365 Days Perpetual Calendars)
Bartlett's Familiar Quotations: A Collection of Passages, Phrases, and Proverbs Traced to Their Sources in Ancient and Modern Literature (17th Edition)