There is no outward mark of politeness that does not have a profound moral reason. The right education would be that which taught the outward mark and the moral reason together.

Johann Wolfgang von Goethe (1749-1832) German poet, statesman, scientist

Elective Affinities, Part 2, ch. 5 (1809) [tr. Hollingdale (1971)]
    (Source)

Alternate translation:

There is no outward sign of courtesy that does not rest on a deep moral foundation. . The proper education would be that which communicated the sign and the foundation of it at the same time.
[Niles ed. (1872)]