In his work, "The Meaning of Becoming a Buddha in This Body," Kobo Daishi says,
"The Six Great-Elements interpenetrate without obstruction and are in eternal union."
This teaches us that the
universal life force, which is comprised of the Six Great-Elements, forms the basis of all things that have life as we do, and that we are in a state of harmony in having the same essence as that of the life of the Buddha.
The great element that is the earth refers to how the Earth is the Mother of life on earth. The great element of water is the water of life that gives moisture to all things and nurtures the power of life. The great element of fire is the energy that is possessed by fire, and is the working of life that gives heat and vitality to living things. The great element of wind is best thought of as the breath of the entire universe, it is constant movement. Each breath we take is life itself. The great element of space is the vast and eternal
life of the universe that envelops all things.
The great element of consciousness is the life of the spirit that is in all things and is the functioning of wisdom.
Shingon Buddhist Intl. Institute: Teachings