The "earth witness" Buddha is one of the most common iconic images of Buddhism. It depicts the Buddha sitting in meditation with his left hand, palm upright, in his lap, and his right hand touching the earth. This represents the moment of the Buddha's enlightenment.
Just before the historical Buddha, Siddhartha Gautama, realized enlightenment, it is said the demon Mara attacked him with armies of monsters to frighten Siddhartha from his seat under the bodhi tree. But the about-to-be Buddha did not move. Then Mara claimed the seat of enlightenment for himself, saying his spiritual accomplishments were greater than Siddhartha's. Mara's monstrous soldiers cried out together, "I am his witness!" Mara challenged Siddhartha--who will speak for you?
Then Siddhartha reached out his right hand to touch the earth, and the earth itself roared, "I bear you witness!" Mara disappeared. And as the morning star rose in the sky, Siddhartha Gautama realized enlightenment and became a Buddha.
The Earth Witness Mudra
A mudra in Buddhist iconography is a body posture or gesture with special meaning. The earth witness mudra is also called the Bhumi-sparsha ("gesture of touching the earth") mudra. This mudra represents unshakability or steadfastness. The Dhyani Buddha Akshobhya also is associated with the earth witness mudra because he was immovable in keeping a vow never to feel anger or disgust at others.
Confirmed by the Earth
I think the earth witness story tells us something else very fundamental about Buddhism. The founding stories of most religions involve gods and angels from heavenly realms bearing scriptures and prophecies. But the enlightenment of the Buddha, realized through his own effort, was confirmed by the earth.
Of course, some stories about the Buddha mention gods and heavenly beings. Yet the Buddha did not ask for help from heavenly beings. He asked the earth. Religious historian Karen Armstrong wrote in her book, Buddha (Penguin Putnam, 2001, p. 92), about the earth witness mudra:
"It not only symbolizes Gotama's rejection of Mara's sterile machismo, but makes a profound point that a Buddha does indeed belong to the world. The Dhamma is exacting, but it is not against nature. . . . The man or woman who seeks enlightenment is in tune with the fundamental structure of the universe."
Buddhism teaches that nothing exists independently. Instead, all phenomena and all beings are caused to exist by other phenomena and beings. The existence of all things is interdependent. Our existence as human beings depends on earth, air, water, and other forms of life. Just as our existence depends on and is conditioned by those things, they also are conditioned by our existence.
The way we think of ourselves as being separate from earth and air and nature is part of our essential ignorance, according to Buddhist teaching. The many different things -- rocks, flowers, babies, and also asphalt and car exhaust -- are expressions of us, and we are expressions of them. In a sense, when the earth confirmed the Buddha's enlightenment, the earth was confirming itself, and the Buddha was confirming himself.