The eighth century Indian monk Santideva ranks among Buddhism's greatest writers. His most important work is a ten-chapter poem entitled The Bodhicaravatara (Introduction to the Practice of the Bodhisattva) which concisely expresses the highest ideals and philosophy of the Mahayama tradition.
The Four Noble Truths are rightly understood as a central -- if not the central -- concepts in Buddhism. Those truths are accepted and venerated by all Buddhists; however, for the Mahayana tradition, the concept of the bodhisattva is equally important. The bodhisattva is a being that has vowed to forever work for the enlightenment of all sentient beings. This amounts to a rejection of the earlier Buddhist traditions which sought to train monks to achieve their own individual enlightenment.
The first step in following the path of the bodhisattva is "bodhicitta," i.e., taking a vow to seek the enlightenment of all sentient beings. Santideva explores a distinction between two forms of bodhicitta: (1) making the determination to follow the path of the and (2) in fact setting out on the path of the bodhisattva. He goes on to explain the characteristics of a bodhisattva which Buddhists have come to name "the six perfections:" generosity, obedience to the moral law, patience or forbearance, energy, meditative stability, and wisdom.
The perfection of wisdom is the highest of these virtues. Santideva provides a seminal treatment of wisdom in the nineth and longest chapter of the poem. Wisdom requires a bodhisattva both to exercise the other five virtues and it is necessary for the perfection of those virtues. Most of all, gaining wisdom requires a true understanding of the world. Crucially, this requires a deep and intuitive understanding of "sunyata," usually translated as "emptiness," and the understanding that all things are empty.
Early Buddhist traditions do make mention of sunyata, but its first full expression appeared in the work of the second century Madhyamaka Buddhist writer Nagarjuna. Santideva's treatment of sunyata is an excellent, concise treatment of Nagarjuna's formulation.
In the course of the work, Santideva presents a method by which one can develop compassion for others, known as "the exchange of self and others." It is based on the idea that to achieve a sympathetic disposition toward all sentient beings, one should proceed in stages. First, one should imagine that the well-being of someone you love, someone very close to you, is as important as your own well-being. This should not be hard. One should then go on to imagine the same is true for others not so close to you and then imagine the same for people for whom you have neutral feelings. Finally, you should imagine that the well-being of people you dislike is as important as your own well-being. By engaging in this exercise, one can develop compassion for all sentient beings and work more easily for their enlightenment.
There are few works more important to the history of Buddhism than The Bodhicaryavatra. It is especially important to Tibetan Buddhism and is often mentioned by the Dalai Lama as the most influential work to his own thinking.
