Reflect upon the inner realities of the universe, the secret wisdoms involved, the enigmas, the inter-relationships, the rules that govern all. For every part of the universe is connected with every other part by ties that are very powerful and admit of no imbalance, nor any slackening whatever. In the physical realm of creation, all things are eaters and eaten: the plant drinketh in the mineral, the animal doth crop and swallow down the plant, man doth feed upon the animal, and the mineral devoureth the body of man. Physical bodies are transferred past one barrier after another, from one life to another, and all things are subject to transformation and change, save only the essence of existence itself -- since it is constant and immutable, and upon it is founded the life of every species and kind, of every contingent reality throughout the whole of creation.
Whensoever thou dost examine, through a microscope, the water man drinketh, the air he doth breathe, thou wilt see that with every breath of air, man taketh in an abundance of animal life, and with every draught of water, he also swalloweth down a great variety of animals. How could it ever be possible to put a stop to this process? For all creatures are eaters and eaten, and the very fabric of life is reared upon this fact. Where it not so, the ties that interlace all created things within the universe would be unravelled.
And further, whensoever a thing is destroyed, and decayeth, and is cut off from life, it is promoted into a world that is greater than the world it knew before. It leaveth, for example, the life of the mineral and goeth forward into the life of the plant; then it departeth out of the vegetable life and ascendeth into that of the animal, following which it forsaketh the life of the animal and riseth into the realm of human life, and this is out of the grace of thy Lord, the Merciful, the Compassionate. ('Abdu’l-Baha, ‘Selections from the Writings of 'Abdu'l-Bahá’; compilation ‘Nature,’ prepared by the Research Department of the Universal House of Justice)