The future painter must feel what is useful for his development – drawing or even sculpture everything that will let him become one with Nature, identify himself with her, by entering into the things – which is what I call Nature – that arouse his feelings. I believe study by means of drawing is most essential. If drawing is of the Spirit and color of the Senses, you must draw first, to cultivate the spirit and to be able to lead color into spiritual paths.

In a letter to Mr. Clifford, February 14, 1948; as quoted in Letters of the great artists – from Ghiberti to Gainsborough, Richard Friedenthal, Thames and Hudson, London, 1963, pp. 238-239