Leverage is everything, — was what I used to say; — don’t begin to pry till you have got the long arm on your side.

Oliver Wendell Holmes, Sr. (1809–1894) American poet, essayist, scholar

Article (1860-08), “The Professor’s Story [Elsie Venner],” ch. 16, Atlantic Monthly, Vol. 6, No. 34
    (Source)

Originally serialized as “The Professor’s Story,” but collected as the novel Elsie Venner, ch. 16 (1861).