Shortly after his Awakening, the Buddha delivered his first sermon, in which he laid out the essential framework upon which all his later teachings were based. This framework consists of the Four Noble Truths, four fundamental principles of nature (Dhamma) that emerged from the Buddha’s radically honest and penetrating assessment of the human condition. He taught these truths not as metaphysical theories or as articles of faith, but as categories by which we should frame our direct experience in a way that conduces to Awakening:
- Dukkha: suffering, unsatisfactoriness, discontent, stress;
- The cause of dukkha: the cause of this dissatisfaction is craving (tanha) for sensuality, for states of becoming, and states of no becoming;
- The cessation of dukkha: the relinquishment of that craving;
- The path of practice leading to the cessation of dukkha: the Noble Eightfold Path of right view, right resolve, right speech, right action, right livelihood, right effort, right mindfulness, and right concentration.
Because of our ignorance (avijja) of these Noble Truths, because of our inexperience in framing the world in their terms, we remain bound to samsara, the wearisome cycle of birth, aging, illness, death, and rebirth. Craving propels this process onward, from one moment to the next and over the course of countless lifetimes, in accordance with kamma (Skt. karma), the universal law of cause and effect. According to this immutable law, every action that one performs in the present moment — whether by body, speech, or mind itself — eventually bears fruit according to its skillfulness: act in unskillful and harmful ways and unhappiness is bound to follow; act skillfully and happiness will ultimately ensue.[13] As long as one remains ignorant of this principle, one is doomed to an aimless existence: happy one moment, in despair the next; enjoying one lifetime in heaven, the next in hell.
The Buddha discovered that gaining release from samsara requires assigning to each of the Noble Truths a specific task: the first Noble Truth is to be comprehended; the second, abandoned; the third, realized; the fourth, developed. The full realization of the third Noble Truth paves the way for Awakening: the end of ignorance, craving, suffering, and kamma itself; the direct penetration to the transcendent freedom and supreme happiness that stands as the final goal of all the Buddha’s teachings; the Unconditioned, the Deathless, Unbinding — Nibbana (Skt. Nirvana).
Note: https://www.accesstoinsight.org