The real mystery isn't that the "light" figures into the fabric of Oneness. It’s that the "darkness" does too.[i]
Jewish mysticism weaves and winds itself in the maze of this mystery. Yet for all its immersion, the maze exhibits blocked regions, temporary pockets of terra incognita.[ii]
The measure of the Messiah is in how far along the maze he’s traveled; how familiar he has become with the mystery of "darkness" ~ not only for his own spiritual success, but for the world’s too.[iii]
Moses mostly engaged the mystery of “light”. Often, he was rebuffed for inquiring about the mystery of “darkness”.[iv] Via his deep familiarity with the “light”, he redeemed a nation from within a nation.
The Messiah is different. He works on teasing out a special reserve of highly intense “light”, the sort encased in the belly of “darkness”. Once exposed, the “darkness” is no longer “darkness”. [v]
His methods aim to redeem whole humanity; as all are in need of redemption, mostly from themselves.[vi]
[i] The Creator’s Oneness is seamless and all inclusive, as it has no “outside”. All is contained within Him. This is explained very well in various sections of “Tanya” by Rebbe Shneur Zalman of Liadi.
[ii] For all the available theological/spiritual explanations there are unanswered questions and broken hearts inflicted by tragedy.
[iii] Jewish tradition ascribes to the Messiah the ability to answer the difficult questions. He’s described in Isaiah as being able to judge situations just by his sense of smell. Often an unresolved Talmud argument ends with the word “Teiku” - which has been explained as an acronym for the “Tishbite (Elijah who heralds the Messiah) will answer the questions and difficulties.”
[iv] A prime example is when he inquired into the martyrdom of Rabbi Akiva or when he wanted the redemption from Egypt to be the final one.
[v] Really there’s only light. Darkness is inverted light or light highly suppressed. I remember reading in Lekutey Moharan of Rebbe Nachman that one day darkness will “vomit” up the sparks of light it has swallowed.
[vi] Most problems people suffer from, whether collectively or individually, are a result of faulty perspective.