The power of words isn't lost on anyone—just think of the pleasure you feel when someone pays you a sincere compliment, or the discomfort of realizing you've spilled a secret you'd promised to keep. Words and the energy they carry make or break friendships and careers; they define us as individuals and even as cultures. We know this, and yet we often let our words flow out more or less unmediated, like random pebbles tossed into a lake. Sometimes, it's only when the ripples spread and cause waves, and the waves rush back and splash us, that we stop to think about the way we speak.
The sages of yoga obviously understood the human tendency to run off at the mouth, because many texts of the inner life, from the Upanishads and the Yoga Vasistha to the Bhagavad Gita, counsel us to use words carefully. The Buddha made right speech one of the pillars of his Noble Eightfold Path. On the simplest level, these sages point out, unnecessary speaking wastes energy that could be devoted to self-inquiry and transformative action. More important, though, is the power that words have to change the communal atmosphere, to cause joy or pain, and to create a climate that fosters truth or falsity, kindness or cruelty.