The following is respectfully quoted from “The Small Golden Key” by Thinley Norbu Rinpoche
According to the teachings of the sūtras, the Buddha turned the Wheel of Dharma, teaching the “four truths” (Tib. bDenpa bash) to the “five noble ones” (Tib. lNga.sde bang.po). These four truths are: suffering, the causes of suffering, the cessation of suffering, and the path leading to cessation of suffering. These are the foundation of the Hinayāna teaching.
Later, at Vulture’s Peak in Rajgir, the Buddha taught the “Perfection of Wisdom” (Skt. Prajñā Pāramitā: Tib. Shes.rab.kyi pa role tu phyin.pa) which is the second turning of the Wheel of Dharma called “Characteristiclessness” (Tib. mutton.nyid med.pa) to the general gathering of the Sangha, including male and female Śramaneras, Bhiksus, and Bhiksuni, and to the special gathering of Bodhisattvas, such as Mañjúshri (Tib. hJam.dpal dByangs), Avalokitesśvara (Tib. sPyan.ras.gzigs), Vajrapāni (Tib. Phya.na rDo.rje) and Maitreya (Tib. Byams.pa).
Finally, at a place of supernatural beings unknown to ordinary beings, the Buddha taught the “Doctrine of Absolute Truth” (Tib. Don.dam rnam.par nges.pa) to various disciples such as Bodhisattvas, gods, nāgas, yachts, rākshas, and humans. At these times, the Buddha exhibited many miraculous powers of body, speech and mind.
The full meaning of Mahāyāna is contained in the Buddha’s last two turnings of the Wheel of Dharma where he taught the actual relative truth and absolute truth.
According to the teachings of the tantras, the higher Vajrayāna teachings were first taught by the Buddha at the request of King Indrabodhi of Uddiyāna (Tib. O.rgyan). In the Vajrayāna teachings, the Buddha taught disciples of superior faculties, who had accumulated great merit, how to transform impure phenomenal appearance into a pure mandala. In order to teach King Indrabodhi, the Buddha emanated the Guhyasamāja mandala (Tib. gSang.ba hDus.pa), then bestowed the empowerment of this mandala upon the king and gave him the tantric teachings.
