But on the other hand, when man does not open his mind and heart to the blessing of the spirit, but turns his soul towards the material side, towards the bodily part of his nature, then is he fallen from his high place and he becomes inferior to the inhabitants of the lower animal kingdom. In this case the man is in a sorry plight! For if the spiritual qualities of the soul, open to the breath of the Divine Spirit, are never used, they become atrophied, enfeebled, and at last incapable; whilst the soul’s material qualities alone being exercised, they become terribly powerful—and the unhappy, misguided man, becomes more savage, more unjust, more vile, more cruel, more malevolent than the lower animals themselves. All his aspirations and desires being strengthened by the lower side of the soul’s nature, he becomes more and more brutal, until his whole being is in no way superior to that of the beasts that perish.
(‘Abdu’l-Bahá, Paris Talks, p. 97)