Basically, price fluctuations have only one significant meaning for the true investor. They provide him with an opportunity to buy wisely when prices fall sharply and to sell wisely when they advance a great deal. At other times he will do better if he forgets about the stock market and pays attention to his dividend returns and to the operating results of his companies.

Chapter II, The Investor and Stock-Market Fluctuations, p. 42 - The Intelligent Investor: The Classic Text on Value Investing (1949)