This is a famous quote. If, after it has been decoded, you don't recognize it... then you fail.
9/6/21 | 20/18/21/6/22/15/16/10 | 20/10 | 16/15/21 | 16/21 | 6/3 | 21/21/2/9 | 19/16 | 16/21 | 6/3.
Slashes separate letters, pipes separate words.
Hint:
It's scrambled... in more ways than one.