J.S. Bach, Air from Suite No. 3, BWV 1068.
'It is as though eternal harmony were conversing with itself, as it may have happened in God's bosom shortly before He created the world.'
Johann Wolfgang von Goethe on Bach
or, to put it more modernly
'I don't think a greater genius has walked the earth. Of the 3 great composers Mozart tells us what it's like to be human, Beethoven tells us what it's like to be Beethoven and Bach tells us what it's like to be the universe.'
(both via BBC 3, A Bach Christmas)