The Zohar says that Eliyahu Hanavi was the Reincarnated soul of Pinchas, the grandson of Aharon, the High Priest. Pinchas was the hero whose act of Zealotry saved the Jewish People from destruction by a deadly plague (Bamidbar 25). Is Reincarnation mentioned in TANACH (The Bible)?

The Ramban and other Kabbalists state that the Book of Ruth teaches the doctrine of Reincarnation (Gilgul Neshamot) by exposition of the following verses. "Boaz married Ruth… and she gave birth to a son." (Ruth 4:13). Then in Ruth 4:17 it says, "A son is born to Naomi." The Ramban explains that this verse is not a TYPO. The verse reveals that Ruth's child was in fact the Reincarnated soul of Naomi's deceased son, Machlon. The name, Machlon, means illness. He became spiritually sick by leaving the Land of Israel and marrying a non-Jewish woman, Ruth. Thus G‑d recycled his soul to become Ruth's child, Oved, which means the servant of G‑d, who became the grandfather of King David.

The Ramban also brings another proof text for Reincarnation from the book of Job, "Wow, all these wonders G‑d does, two or three times with a person. To bring back his soul from the grave, to light up his life with the living light." (Job 33:29-30).

Why is there Reincarnation? Life works the way that education works, which is about moving up from level to level as one matures and becomes more intelligent. The educational process that we go through in life is meant to enhance a person's ability to function in the world and to help people make the most of their lives. Life is about our need to become responsible members of society.

As a person grows up, his spiritual capabilities also increase and mature but not automatically. The more one puts into an education the more one derives from it. Similarly the more one puts into spiritual growth, the more one grows spiritually, and the more spiritually empowered one becomes. This process of spiritual growth enables one to enjoy and delight in G‑d's presence for eternity in the Afterlife.

Kabbalah teaches that though we all have one, special soul, each soul is actually comprised of five parts, each of which has a specific name – Nefesh, Ruach, Neshamah, Chaya, and Yechidah. Nefesh is the life force. Ruach is the spirit. Neshamah is the breath of life. Chaya is the living soul, and Yechidah is the unique soul. These soul parts represent the path to spiritual completion and perfection, because each level up provides increasingly greater access to higher levels of spiritual capacity and eternal closeness to G‑d.

At birth every individual has all five levels of soul. We have to if we are going to continuously receive G‑d's light to keep us functioning, since the five levels of soul connects us to the light of G‑d which nourishes our souls and keeps our bodies alive. To be missing a level of soul would be to break the connection between a person and G‑d, the Source of Life.

The Torah gives a person access to higher levels of spiritual understanding and to the perfection of the soul. The problem is that the Evil Inclination can interfere with our ability to climb the soul ladder from Nefesh to Ruach to Neshamah, etc. so much so that time can run out on our lifetime before we are done. People often remain stuck on the lowest levels of soul for decades, or even entire lifetimes. G‑d can't afford to give up on any soul as Job 31:2 states, "Chelek Alokai mimaal" (We are a portion of my G‑d from above.) Thus there is Reincarnation. We return to complete and perfect what we started in other lifetimes even if we aren't aware of who we were or where we were. The Hebrew word for Reincarnation is Gilgul which means recycling.

The word GILGUL in Hebrew, Gimmel Lamed Gimmel Vav Lamed, has the numerical value (GEMATRIA) of the word CHESED, Chet Samech Dalet, lovingkindness, which both equal the number 72 which is one of G‑d's Mystical Names, Shem Ayin Bet = 72. When this type of numerical connection occurs, it implies a profound, conceptual relationship. GILGUL is the ultimate CHESED of G‑d, in that a soul is given another chance for the refinement of its past and the spiritual growth and advancement of its future.

To succeed in Eternity, a soul must return to this physical world again and again to do its TIKKUN (correction / fixing) and to fulfill its spiritual mission.