Philonis Judaei Opera Omnia (Vol. 7)

And by these, they are kindled like lamps of fire, virtues that are swifter in motion and more effective, burning indeed like fiery divine utterances, sometimes preserving the whole universe intact with one another, sometimes purging away superfluous darkness. Nevertheless, properly and more familiarly, such a reason must be rendered: human life is similar to a smoking furnace, in that it does not have pure fire and bright light, but manifold smoke through a flame that smokes more obscurely, which causes gloom and darkness and obscuration—not of the body, but of the soul—so that it is not permitted for it to see clearly; until the Redeemer God commands celestial lamps to arise, purer and holier radiations, I say, which associate and illuminate those two divided parts to the right and left, being the causes of harmony and luminous clarity.

Why did He say: On that day He made a covenant with Abraham, saying: To your seed I will give this land from the river of Egypt to the great river Euphrates? Genesis 15:18

§. 16. The literal sense delineates the boundaries of the space lying in the middle of both rivers, of Egypt and the Euphrates; for in ancient times, the river of the region of the same name was also called Egypt: which the poet also testifies, saying: Stand in the river Egypt, ships crossing from both sides Homer, Odyssey XIV, 258. original Greek: "στῆσα δ᾽ ἐν Αἰγύπτῳ ποταμῷ νέας ἀμφιελίσσας.". To the mind, however, it hints at happiness, which is the perfect fullness of threefold goods: namely spiritual, bodily, and external: as some of those who later became philosophers celebrate it with praise, Aristotle with the Peripatetics; it is said, however, that such legislation is also Pythagorean. Therefore, Egypt is the symbol of bodily and external goods, while the Euphrates is the symbol of spiritual goods, in which alone true joy consists, having its source in wisdom along with all the virtues.