The Sūtra of the Wheel of Dharma
The Sūtra of the Wheel of Dharma contains the Buddha’s teaching to his five former spiritual companions on the four truths that he had discovered as part of his awakening: (1) suffering, (2) the origin of suffering, (3) the cessation of suffering, and (4) the path leading to the cessation of suffering. According to all the Buddhist traditions, this is the first teaching the Buddha gave to explain his awakened insight to others.