Johannes Brahms wrote to Clara Schumann. whom he greatly admired:
It is from you that I am constantly learning that one cannot obtain vital force out of books, but only out of one’s soul. One must draw inspiration not from without, but from within.
Cited in: Goss, Madeleine & Schauffler, Robert (1943) Brahms The Master. New York: Henry Holt and Company, p.152.