 
                            
                        
                        
                        “Let every man look before he leaps.”
Source: Don Quixote de la Mancha (1605–1615), Part II (1615), Book III, Ch. 14.
            Part I, chapter 2. 
Proverbs (1546)
        
“Let every man look before he leaps.”
Source: Don Quixote de la Mancha (1605–1615), Part II (1615), Book III, Ch. 14.
                                        
                                        Canto II, line 501 
Source: Hudibras, Part II (1664)
                                    
The Roxburghe Ballads (c. 1630), reported in Bartlett's Familiar Quotations, 10th ed. (1919).
“You're leaping over the hedge before you come to the stile.”
Source: Don Quixote de la Mancha (1605–1615), Part I, Book III, Ch. 4.
                                        
                                        1956 - 1967 
Source: the 'Ad Reinhardts Papers', Archives of American Art, microfilm no. N/69-103, frame no. 268
                                    
Source: When Gravity Fails (1986), Chapter 2 (p. 20).
Malcolm Gladwell, in Cheryl Glenn, et al Harbrace Essentials http://books.google.co.in/books?id=WWgIAAAAQBAJ&pg=PT165, Cengage Learning, 1 January 2011, p. 165
 
                            
                        
                        
                        