In Aramaic, nun means "fish." The mem, the waters of the sea, is the natural medium of the nun, fish. The nun "swims" in the mem, covered by the waters of the "hidden world." Creatures of the "hidden world" lack self-consciousness. Unlike fish, land animals, revealed on the face of the earth, possess self-consciousness.
The souls of Israel divide into two general categories, symbolized by fish and land animals. The two prototypes of these categories are the leviathan and the behemot. In the present, these two categories of souls correspond to the two innate tendencies and attractions of the soul, to either the concealed and secret or revealed and legal dimensions of Torah. In the future, the two prototypes, leviathan and behemot, will unite in battle, each "killing" the "ego" of the other, thereafter to blend together in true union. Their "meat" will then be served as the feast for the tzadikim in the World to Come. The souls of the tzadikim will actually consume the very root of consciousness of our present level of soul, in order to integrate ("digest") it into a totally new and higher level of consciousness.
"Leviathan" equals in gematria malchut, ("kingdom," 496). In Kabbalah, malchut, in the world of Divine Emanation, is represented by the sea, whose tides are controlled by the power of the moon, the symbol of King David (upon seeing the new moon we say, "David the king of Israel is alive forever"). When malchut descends to enliven the lower worlds it is symbolized by the earth. Thus, the leviathan is the symbol of the Divine Source of "kingdom." In Hebrew, nun means "kingdom," and in particular, the "heir to the throne."
The "nun" is the fourteenth letter of the alef-beit, which equals "David," the progenitor of the eternal Kingdom of Israel. The heir to David is Mashiach ben David, of whom is said: "As long as the duration of the sun his name shall rule." Our Sages teach us that one of the names of Mashiach is Yinon ("shall rule"), cognate to nun. Mashiach is also referred to as "the miscarriage," or, literally, the "fallen one." As we will learn in the secret of the letter samech, the nun does not appear in Psalm 145, but is supported by God's transcendent mercy, as expressed by the following letter, samech. In general, nun corresponds in Torah to the image of falling. The soul of Mashiach experiences itself as continuously falling and dying; if not for the ever-present Hand of God "catching" it, it would crash to the ground and shatter to death. The consciousness of fall is the reflection of the egoless state of the fish, in its natural medium of water, when forced to reveal itself on dry land. This is like the experience of a hidden tzadik when forced from Above to reveal himself for the good of Israel and the world. We find this exemplified in the life and teachings of the Ba'al Shem Tov, and so will be epitomized in the life of Mashiach. Ultimately, the "destiny" of Mashiach and his generation is to assume the level of sea on earth, to experience, paradoxically, selfless-self-consciousness, as said in the verse of Isaiah with which Maimonides concludes his Code of Jewish Law (whose final section, "The Laws of Kings," culminates with the description of the coming of Mashiach): "for the earth will be filled with the knowledge of God, like waters cover the sea."
A "bent-over" vessel - the "bent-over servant."
The final nun - an extended vav descending below the line - the "unbounded servant."
Fish; kingdom; heir to the throne.
Fifty; the fifty gates of understanding.