We’re taught that all five of the Partzufim — the primary clusters of Sephirot that comprise the makeup of the Worlds, hence all the elements of reality — are rooted in G-d’s primary name Yud, Hay, Vav, and Hay (Eitz HaChaim, Sha’ar HaKlallim 2). The five parts of the Neshama are also rooted in that name. “The Neshama of the Neshama (i.e., Chaya and Yechidah according to Ma’amar HaNephesh 1:3, as indicated above) is contingent upon the Yud (apparently with the tip of the Yud standing for the Yechidah and the body of the Yud standing for the Chaya), … the (first) Hay is termed Neshama … the Vav is termed Ruach … and the (final) Hay is termed Nephesh … (Zohar Chadash Rut 78c). (We wonder why the Neshama of the Neshama is said to be “contingent upon” the Yud, while the other parts of the Neshama are only said to be “termed” one letter or another.)
Elsewhere we’re told that Nephesh is in the category of G-d’s name El-ohim; Ruach is Yud, Hay, Vav, and Hay; Neshama is Yud, Hay, Vav, and Hay in a “Full State” (Malei); and Neshama of the Neshama is Yud, Hay, Vav, and Hay in an “Utterly Full State” (Malei shel Malei)(Eitz Chaim, Sha’ar Klipat Nogah 3).
And others say that Nephesh, Ruach and Neshama correspond to Kohen, Levi and Yisrael (Tikkunei Zohar 70, p. 136a), or that Nephesh corresponds to a candle-wick, Ruach corresponds to olive-oil, and Neshama corresponds to a candle itself (termed Ner which is spelled Nun and Resh) corresponding to the phrase “The candle of G-d is the soul of man” (Proverbs 20:27) (Tikkunei Zohar 21, p. 49b; also see Zohar 3, p. 187a). Abraham is said to correspond to the Neshama of the Neshama, Sara to the Neshama, Isaac to the Ruach, and Rebecca to the Nephesh (Zohar 1, p. 79b).