In this video Bernstein introduces in a very simple and effective way, what the listeners should expect from a performance of the Bach’s Concerto No.1 in D minor (BWV 1052) by him, Gould and the New York Philharmonic Orchestra. Gould here is 28 years old.
The whole concert is at the bottom of the page.
The Goldberg Variations from J. S. Bach, played by Glenn Gould in 1981 (first video) and 1955 (second video). 26 years before.