Dhammacakkappavattana Sutta: Setting the Wheel of Dhamma in Motion
The four true realities taught by the Buddha are not as such things to "believe" but to be open to, see and contemplate, and respond to appropriately: by fully understanding dukkha/pain/the painful, abandoning that which originates it, personally experiencing its cessation, and cultivating the path that leads to this. These four true realities are the four fundamental dimensions of experience, as seen by a spiritually noble person with deep wisdom: the conditioned world, that which originates it, the cessation/transcending of it (the unconditioned, Nibbāna), and the path to this. Indeed, it is by insight into these that a person becomes spiritually ennobled.
Dhammacakkappavattana Sutta: Setting the Wheel of Dhamma in Motiontranslated from the Pali byThanissaro Bhikkhu© 1993–2012"And, monks, as long as this — my three-round, twelve-permutation knowledge & vision concerning these four noble truths as they have come to be — was not pure, I did not claim to have directly awakened to the right self-awakening unexcelled in the cosmos with its deities, Maras, & Brahmas, with its contemplatives & brahmans, its royalty & commonfolk. But as soon as this — my three-round, twelve-permutation knowledge & vision concerning these four noble truths as they have come to be — was truly pure, then I did claim to have directly awakened to the right self-awakening unexcelled in the cosmos with its deities, Maras & Brahmas, with its contemplatives & brahmans, its royalty & commonfolk. Knowledge & vision arose in me: 'Unprovoked is my release. This is the last birth. There is now no further becoming.'"