Every book is a quotation; and every house is a quotation out of all forests and mines and stone quarries; and every man is a quotation from all his ancestors. – Ralph Waldo Emerson, “Plato; Or, The Philosopher”

Do not shun this maxim because it is common-place. On the contrary, take the closest heed of what observant men, who would probably like to show originality, are yet constrained to repeat. Therein lies the marrow of the wisdom of the world. – Arthur Helps, “Chapter IV,” Companions of My Solitude, 1851

I often quote myself. It adds spice to my conversation. – George Bernard Shaw

The wise men of old have sent most of their morality down the stream of time in the light skiff of apothegm or epigram; and the proverbs of nations, which embody the commonsense of nations, have the brisk concussion of the most sparkling wit. – Edwin P. Whipple, lecture delivered before the Boston Mercantile Library Associa