Rambam - Sefer HaMitzvos: Negative Mitzvah 167: Negative Mitzvah 167

Negative Mitzvah 167: The High Priest is forbidden to be under the same roof as a dead body
Leviticus 21:11 "Neither shall he come close to any dead body"

A High Priest must always keep himself in a state of purity.

Unlike a regular priest who may become impure from contact with his closest relatives who have died (see Negative Mitzvah 166), a High Priest may not become impure from contact with any dead body.

This Negative Mitzvah cautions a High Priest to be careful not to be under the same roof as a dead body, even if it is one of his seven closest relatives.

No one has ever seen, touched or measured a particle or a wave of gravity. Furthermore, the very notion of gravity is mystifying: Masses light years apart with nothing in between, affecting each other's movements!
Yet we all accept there must be a cause behind the phenomenon we observe, so we call this elusive force "gravity".
So too, there is a cause behind existence. That Cause may be even more elusive, but the reality of its existence is at least as inescapable.

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The Rebbe writes in a letter: Before I had even started school, a picture of liberation was already forming in my mind. Such a liberation, and in such a way, that it shall truly make sense of all the suffering, all the oppression and persecution we have undergone. It is not that there will be no more darkness, no more suffering, that those things shall cease to exist. It will be such an essence-light that darkness itself will become light -- even the darkness and suffering of the past.

From: Bringing Heaven Down to Earth by Tzvi Freeman - tzvif@aol.com