Inayat Kahn (1882-1927) was founder of the Sufi Order in the West as well as the author of The Art of Personality.
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There is nothing of this earth more valuable than the seed of man, the source of further manifestation. By its loss every door of happiness in life is closed. But man is usually so careful with his money and property and jewels, and desires so earnestly to increase them, that he sacrifices everything to them.
And he becomes regardless of the jewel of life which is his own life, character, and personality, and which is more precious than any property.
The Sufi Message of Hazrat Inayat Khan by Hazrat Inayat Khan. Volume 3 The Art of Personality.