The Four Noble Truths, which include the Eightfold Path, describe the
true nature of existence, and the means to live in harmony with that
nature.
By tradition, the preaching of the Four Noble Truths
was the first sermon given by the Buddha, after he became the Awakened
One.
It could be said that The Four Noble Truths, and what they
infer, are Buddhism itself. There are many traditions, schools, sects
of Buddhism, but the Four Noble Truths are acknowledged in all of them,
because they are foundational. They describe why Buddhism is needed, and
what constitutes the essence of the practice of Buddhism. There may be
various practices and ideas within Buddhism, but they are merely
different expressions of the essence as expressed in the Four Noble
Truths.
