Returning in the flesh, Jewish style
According to current Jewish tradition, the belief in the resurrection of the dead is a principal article of faith:
“And these are the ones that will not have a portion in the World to Come: One who says that the resurrection of dead is not of biblical origin.” (Mishnah Sanhedrin 10:1)
(Incidentally, this means that if you don’t believe in heaven, you will not gain entrance to heaven. Which, I am afraid, won’t really scare anyone that doesn’t believe in heaven in the first place.)
Resurrection creates an obvious problem: After a person dies, the body disintegrates to such an extent that resurrecting it as is will not be feasible. Even better: sometimes there is nothing left of a body, e.g. when a body was burnt.
How does Judaism deal with this theological problem?
As it often does, the answer needs a miracle. The Rabbis believe that there is a bone in the human body from which the body is rebuilt after the resurrection. This is what is called the Luz bone. As stated in Bereishit Rabba 28:3:
“And G’d said: ‘I will wipe away mankind’... Hadrian was [once] grinding bones. He asked Rabbi Yehoshua ben Chananyah: ‘From where does the Holy One Blessed be He reconstruct man in the future to come?’ He answered him: ‘From [the] Luz of the spine.’ Said he: ‘From where do you know this?’. He said: ‘It has come to me [it was delivered to me as a tradition] and I will show you.’ They tried to grind it in a mill but it was not ground, they burnt it in fire but it was not consumed, they put it in water but it was not softened, they put it on an anvil and he started to beat it with a hammer but the anvil slipped, the hammer was broken and it remained intact.”
Incidentally, muslims also believe in the Luz myth and call it "^Ajbu al-Thanab" (عَجْبُ الذَّنَب). At least something Muslims and Jews agree on!
However, it seems to be that the chiddush of the Luz bone was not entirely ours. The JewishEncyclopedia.com website brings the following:
Possibly the legend owes its origin to the Egyptian rite of burying "the spinal column of Osiris" in the holy city of Busiris, at the close of the days of mourning for Osiris, after which his resurrection was celebrated (Brugsch, "Religion und Mythologie," 1888, pp. 618, 634).
Now everybody knows that if you cremate a corpse that only ashes are left. Even the Ohr Somayach website says in an article on cremation (disagreeing with the Midrash):
“Furthermore, one who has his body cremated will not merit resurrection a fundamental belief of Judaism expressed in Maimonides' 13 Principles of Faith: I believe with complete faith that there will be a resurrection of the dead, when the wish emanates from the Creator. One explanation is that cremation destroys even the extremely hard luz bone from which a buried body is reconstituted.”
The fantasy only starts from there. Same web site, different article:
It [the Luz bone] has curious properties: It receives nourishment only from food eaten Saturday night at the melave malka meal (Mishna Berurah 300:2 in the name of some ‘kadmonim’).
Rabbi Asher Meir from on the OU website adds:
“The Eliah Rabbah relates a remarkable tradition explaining the connection between the LUZ and melave malka. He points out that originally, the entire body was indestructible; Adam and Chava were meant to live forever.
Death was decreed for them only because they ate of the fruit of the Tree of Knowledge. However, one tiny bone was not nourished by this fruit, the LUZ, which is only nourished by the Saturday night meal! Thus this bone retained its original, pre-fall immortality.”
Meir goes on to explain that Motzaei Shabbat is the day after Shabbat, the day representing Olam Haba and that Motza’ei Shabbat exudes a higher level of perfection. Therefore:
“this special limb was created to be nourished and cultivated only in an environment of perfected development.”
Note that association between ‘Luz’ and defying death was already hinted at in Bereishit Rabbah 69:8. There it tells us about the city of Luz and its magical powers over death:
“This is the same Luz that the Angel of Death never had power over.”
Bone of contention
Instead of scientificillay trying to prove where the bone can be found, i.e. testing where this strongest bone really is to be found, there is a difference of opinion. After all, chazal would have nothing to teach if we didn’t have a machloket about every single thing, regardless of its sillyness.
The Arizal and Chida hold that it is located in the place where the knot of the tefillin is placed. This certainly sounds more mystical than some other commentators (including Aruch, Rokeach, Recanati) who believe that the Luz bone is located at the bottom of the spine and that it is nothing less than the tail bone (Coccyx), which incidentally is believed to be evidence for evolution.
And you know that many Rabbis believe that not believing in evolution is almost an article of faith. Just as belief in the resurrection is!