Soul
Judaism

The Hebrew terms נפש nefesh (literally "living being"), רוח ruach (literally "wind"), נשמה neshamah (literally "breath"), חיה chayah (literally "life") and יחידה yechidah (literally "singularity") are used to describe the soul or spirit. In Judaism, there was originally little to no concept of a soul. As seen in the Genesis, the divine breath simply animated bodies.

Then Yahweh God formed man of dust from the ground and breathed into his nostrils the breath of life; and so the man became a living being.

Judaism relates the quality of one's soul to one's performance of the commandments (mitzvot) and reaching higher levels of understanding, and thus closeness to God. A person with such closeness is called a tzadik. Therefore, Judaism embraces the commemoration of the day of one's death, nahala / Yahrtzeit, and not the birthday, as a festivity of remembrance, for only toward the end of life's struggles, tests and challenges could human souls be judged and credited for righteousness. Judaism places great importance on the study of the souls.

Kabbalah and other mystic traditions go into greater detail into the nature of the soul. Kabbalah separates the soul into five elements, corresponding to the five worlds:

Kabbalah proposed a concept of reincarnation, the gilgul (nefesh habehamit – the "animal soul"). Some Jewish traditions assert that the soul is housed in the luz bone, though traditions disagree as to whether it is the atlas at the top of the spine, or the sacrum at bottom of the spine.
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