A noble man compares and estimates himself by an idea which is higher than himself; and a mean man by one which is lower than himself. The one produces aspiration; the other, ambition. Ambition is the way in which a vulgar man aspires.

Henry Ward Beecher (1813-1887) American clergyman and orator

Life Thoughts (1858)
    (Source)

Sometimes misattributed to Marcus Aurelius.