"It is as foolish to make experiments upon the constancy of a friend, as upon the chastity of a wife."

Source: James Boswell, Samuel Johnson, Edmond Malone (1824). “The life of Samuel Johnson, LL. D., comprehending an account of his studies, and numerous works, in chronological order: a series of his epistolary correspondence and conversations with many eminent persons; and various original pieces of his composition, never before published; the whole exhibiting a view of literature and literary men in Great Britain, for near half a century during which he flourished”, p.378