[W]hereas the Hinayāna sūtras and schools do not recognize that sentient beings universally possess the nature of buddhahood, the Flower Garland Sūtra states that right after his awakening the Buddha saw that all beings are capable of being buddhas also but do not realize it.

Then the Buddha, with the unimpeded, pure, clear eye of knowledge, observes all sentient beings in the cosmos and says, “How strange — how is it that these sentient beings have the knowledge of the Buddha but in their folly and confusion do not know it or perceive it? I should teach them the way of sages and cause them forever to shed deluded notions and attachments, so they can see in their own bodies the vast knowledge of buddhas, no different than the buddhas. (Cleary 1993, p. 1003)

In the Nirvāṇa Sūtra, just before his final nirvāṇa the Buddha teaches that the essential nature of the Buddha is unborn and deathless and that all beings are endowed with this same buddha-nature.

“This is to say that the Tathagata is eternal and unchanging, that he is utmost peace itself, and that all beings have the Buddha Nature. ” (Yamamoto, Kosho, p. 143)

Though the buddha-nature of all sentient beings is asserted, the Buddha stated in the passage from the Flower Garland Sūtra that sentient beings are ignorant of this and would need to be taught. In the Nirvāṇa Sūtra, Kāśyapa Bodhisattva points out:

“There surely is the Buddha Nature. But having not yet practiced the best expediency of the Way, he has not yet seen it. Having not seen it, there can be no attainment of the unsurpassed bodhi. ” (Ibid, p. 169)

Having buddha-nature, then, is one thing, but actually arousing the aspiration to attain buddhahood and making efforts to realize and actualize buddha nature is something else again. This aspiration and determination to dedicate all their efforts to attaining buddhahood for the sake of all beings is what differentiates a bodhisattva from the śrāvakas and pratyekabuddhas of the two vehicles.