Bodhisattva is the Buddhist term for someone with great compassion whose life work is to ease people's suffering. Buddhism talks about a bodhisatttva named Avalokiteshvara, the Bodhisattva of Deep Listening. The name Avalokiteshvara means "the one who listens deeply to the sounds of the world."
According to Buddhist tradition, Avalokiteshvara has the capacity to listen to all kinds of sounds that can heal the world. If you can find silence within yourself, you can hear the five sounds.
The first is the Wonderful Sound, the sound of the wonders of life that are calling you. This is the sound of the birds, of the rain, and so on.
The second sound is the Sound of the One Who Observes the World. This is the sound of listening, the sound of silence.
The third sound is the Brahma Sound. This is the transcendental sound, om, which has a long history in Indian spiritual thought. The tradition is that the sound om has the innate power to create the world. The story goes that the cosmos, the world, the universe was created by that sound.
The fourth sound is the Sound of the Rising Tide. This sound symbolises the voice of the Buddha. The teaching of the Buddha can clear away misunderstanding, remove affliction, and transform everything. It's penetrating and effective.
The fifth sound is the Sound That Transcends All Sounds of the World. This is the sound of impermanence, a reminder not to get caught up in or too attached to particualr words or sounds. Many scholars have made Buddha's teaching complicated and difficult to understand. But the Buddha said things very simply and did not get caught up in words. So if a teaching is too complicated, it's not the sound of the Buddha. If what you're hearing is too loud, too noisy, or convoluted, it's not the voice of the Buddha. Wherever you go, you can hear that fifth sound. Even if you're in prison, you can hear the Sound That Transcends All Sounds of the World.
From the book "Silence" by Thich Nhat Hanh