Nephesh
(Hebrew נפש; alternatively, nefesh) In Kabbalah, one of the three aspects of the soul. The word means "vitality, life force, blood, breath of life, soul, appetite." The animal soul.
"And the LORD God formed man [of] the dust of the ground, and breathed into his nostrils the breath [נשמה neshamah] of life; and man became a living soul [nephesh נפש]." —Genesis 2:7
“All the labour of Adam is for his mouth, and yet the nephesh [appetite] is not filled.” —Ecclesiastes 6:7
"The soul is a trinity. It comprises three elements, viz.: (a) Neshāmāh, the rational element which is the highest phase of existence; (b) Ruaḥ, the moral element, the seat of good and evil, the ethical qualities; (c) Nefesh, the gross side of spirit, the vital element which is en rapport with the body, and the mainspring of all the movements, instincts, and cravings of the physical life. There is a strong reflection of Platonic psychology in these three divisions or powers of the soul. More than one mediæval Jewish theologian was a Platonist, and in all probability the Zohar is a debtor to these. The three divisions of the soul are emanations from the Sefirot. The Neshāmāh, which, as has been said, is the soul in its most elevated and sublimest sense, emanates from the Sefirah of Wisdom. The Ruaḥ, which denotes the soul in its ethical aspect, emanates from the Sefirah of Beauty. The Nefesh, which is the animal side of the soul, is an emanation from the Sefirah of Foundation, that element of divinity which comes, most of all, into contact with the material forces of earth." —Jewish Mysticism by J. Abelson [1913]
"The Hebrew nefesh (soul) is a homonymous noun, signifying the vitality which is common to all living, sentient beings. E.g. "wherein there is a living soul" (nefesh) (Gen. i. 30). It denotes also blood," as in "Thou shalt not eat the blood (nefesh) with the meat" (Deut. xii. 23). Another signification of the term is "reason," that is, the distinguishing characteristic of man, as in "As the Lord liveth that made us this soul" (Jer. xxxviii. 16). It denotes also the part of man that remains after his death (nefesh, soul) comp. "But the soul (nefesh) of my lord shall be bound in the bundle of life (1 Sam. xxv. 29). Lastly, it denotes "will"; comp. "To bind his princes at his will" (be-nafsho) (Ps. cv. 22); "Thou wilt not deliver me unto the will (be-nefesh) of my enemies" (Ps. xli. 3); and according to my opinion, it has this meaning also in the following passages, "If it be your will (nafshekem) that I should bury my dead" (Gen. xxiii. 8); "Though Moses and Samuel stood before me, yet my will (nafshi) could not be toward this people" (Jer. xv. 1), that is, I had no pleasure in them, I did not wish to preserve them. When nefesh is used in reference to God, it has the meaning "will," as we have already explained with reference to the passage, "That shall do according to that which is in my will (bi-lebabi) and in mine intention (be-nafshi)" (1 Sam. ii. 35). Similarly we explain the phrase, "And his will (nafsho) to trouble Israel ceased" (Judg. x. 16)." —Moses Maimonides
"The Initiate must descend into the infernal worlds during forty-days and has to recapitulate all of the evil deeds and frightful dramas of his past incarnations; little by little, the Initiate departs from these tenebrous regions. Before departing, the three souls, Nephesh (Animal Soul), Ruach (Thinking Soul) and Neshamah (Spiritual Soul) are submitted to ordeals. How interesting it is to see the animal soul submitted to ordeals, as well as the thinking soul and the Essence (Part of Neshamah) that also is submitted to ordeals. The Bible states, "Nephesh, Nephesh, blood is paid with blood." Within the Hebrew words wisdom is hidden." —Samael Aun Weor, Tarot and Kabbalah