[T]o talk well and eloquently is a very great art, but that an equally great one is to know the right moment to stop.
Source: Letter, 4 Nov 1787; in The Letters of Mozart and His Family, 1966.
-- Wolfgang Amadeus Mozart, (Jan 27 1756-1791), Austrian composer; He was child prodigy who composed 600+ works - chamber music, symphonies and operas, e.g., The Magic Flute, 1787.