Sefer haChinukh on the World to Come not Mentioned in the Written Torah

"Should one ask further: After you have said that the primary aspect of all Creation is the world of souls (olam ha-neshamot) and that the ultimate reward for observance of the mitzvot is received there, why does God not mention it in the Written Torah and say explicitly, 'When you perform My mitzvot, I will bequeath you a share in the World to Come'?

"The answer is as follows: It is because the idea of the World to Come is known and obvious to all who possess intelligence; it is as clear as the sun. There is no nation or culture that does not agree that souls endure after the bodies have ceased to be; nor is there anyone who disputes that commensurate with the goodness of a soul, its wisdom, and the righteousness of its deeds, its pleasures in that world is correspondingly greater.

"This is logical, for the origin of the intelligent soul is the Source of Intelligence, i.e. God, and the closer the soul draws to its natural environment, to the place from which it originates, the greater is its pleasure."

-- Sefer haChinukh, Introduction

While the anonymous author of the Chinukh was well versed in the thought of Maimonides, who was thoroughly of Aristotelian persuasion, this passage is very similar to Platonist doctrines on the soul, such as found in Phaedrus, Philebus, etc.