The last quality, perseverance, I particularly respect: it is the very hinge of all virtues. — On looking over the world, the cause of nine parts in ten of the lamentable failures which occur in men’s undertakings & darken and degrade so much of their history, lies not in the want of talents or the will to use them, but in the vacillating and desultory mode of using them — in flying from object to object, in starting away at each little disgust, and thus applying the force which might conquer any one difficulty to a series of difficulties so large that no human force can conquer them. The smallest brook on earth, by continual running, has hollowed out for itself a considerable valley to flow in: the wildest tempest, by its occasional raging, over-turns a few cottages, uproots a few trees, and leaves after a short space no mark behind it. Commend me therefore to the Dutch virtue of perseverance! Without it all the rest are little better than fairy gold, which glitters in your purse, but when taken to the market proves to be — slate or cinders.

Thomas Carlyle (1795-1881) Scottish essayist and historian

Letter to John Carlyle (15 Mar 1822)
    (Source)