The Buddha said to Sāriputra: “The Buddha-Tathāgatas teach only the bodhisattva doctrines [that transform sentient beings into bodhisattvas]; all the acts of Buddhas are solely to demonstrate the knowledge and insight of Buddha to bring sentient beings to enlightenment. Sāriputra! The Tathāgatas teach the Dharma to sentient beings through only the single Buddha Vehicle; they have no other vehicles—no second or third vehicle. Sāriputra! Buddhas of the ten directions and their instructions are all like this.”
Translation of the scriptural passage referenced the rendition of Gene Reeves. [Reeves, G. (2008). The Lotus Sutra: A Contemporary Translation of a Buddhist Classics. Boston: Wisdom Publications, pp. 83-84.]
The innumerable Buddhas of the past, the present, and the future in the worlds of ten directions expound the single Buddha Vehicle to make known that no Buddha-Tathāgata will depart from the human world after teaching only the Dharma of the Two Lesser Vehicles. A Buddha descends and manifests in the human world for the purpose of demonstrating the single Buddha Vehicle, which is the Great Vehicle that subsumes the Two Lesser Vehicles. The complete cultivation of the Great Vehicle enables one to acquire the knowledge-of-all-aspects and arrive at the ultimate Buddha Ground. This is the real purpose of all Buddhas’ manifestation in the human world.
A Discourse on the Lotus Sutra, Vol. 2, pp. 291-292