We have spoken of the pure and true mind as being fundamental; it is the Buddha-nature, that is, the seed of Buddhahood. (pg. 140)
However buried in the defilement of flesh or concealed at the root of worldly desires and forgotten it may be, the human affinity for Buddhahood is never completely extinguished. (pg. 144)
— Buddha
from "The Teaching of Buddha"
(Bukkyō Dendō Kyōkai)