Who are the Bodhisattvas and what is meant by the hearts of Bodhisattvas? Bodhisattvas seek to save other people besides themselves, just as the Buddha did. The Bodhisattva heart is the same as the Buddha heart. It does not take much study or diligent practice to know the heart of the Buddha and make it one’s own. The Buddha is a symbol of the human ideal. Even an ignorant person can experience the Buddha’s heart by dedicating his or her own heart to Him, exalting Him as the ideal, wishing to follow His teachings, believing in and praying to Him, and putting such thoughts into practice to the best of one’s ability. It is possible for anyone to experience the heart of the Buddha; that is a way of Practice which is open to anyone. For example, someone who is trying to help another person or persons (the Bodhisattva Practice) is already experiencing the Buddha in his heart. Such a potential for realizing Buddhahood in one’s heart is something every one of us already possesses by nature. (The Buddha was a human being, and so are we; he achieved Buddhahood, and so can we.) This potential is called the “Buddha-nature.”
Introduction to the Lotus Sutra