Bodhi Mind is a strong, steadfast aspiration to seek Truth. This is the purpose of practice, the purpose of the spiritual life. “To arouse this determination,” said Dogen, “it is necessary to earnestly contemplate the impermanence of the world.” We have to see the truth of how transient the world is and how fragile human life is. Impermanence is the Truth that everything, without exception, is motion. There is just continuous change. Your body and mind—all things—are nothing but change itself.
From You Have to Say Something: Manifesting Zen Insight by Dainin Katagiri, page 39.