This is a study and translation of the Mahayana Sutra, Bodhisattvagocara, which contains one of the only Buddhist teachings extant on what might be called a "Buddhist theory of national defense." It contains a dialogue between Sakyamuni Buddha and the Nirgrantha sage, Satyaka, who is revealed at the end to be a bodhisattva of high attainment. The text has been seminal in the ethical reflections of generations of Indian and Tibetan Buddhists, though it was not well known in East Asia.