The “fountain-head of all calamities”, and man’s “supreme affliction”

And among the teachings of His Holiness Bahá'u'lláh is man's freedom, that through the ideal power he should be free and emancipated from the captivity of the world of nature; for as long as man is captive to nature he is a ferocious animal, as the struggle for existence is one of the exigencies of the world of nature. This matter of the struggle for existence is the fountain-head of all calamities and is the supreme affliction. (Abdu'l-Baha, Tablet to the Hague)