Rambam - Sefer HaMitzvos: Positive Mitzvah 99: Positive Mitzvah 99

Positive Mitzvah 99: Impurity of a "Niddah"
Leviticus 15:19 "When a woman has a discharge..."

Niddah is a state of impurity that applies only to women.

The very fact you know about someone who is in trouble means that in some way you are able to help. Otherwise, why would this knowledge have entered your world?

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Arik Sharon, when he was Israeli Minister of Defence, came to visit the Rebbe. After his private audience, he related to his friends, "The Rebbe was very cordial. He asked when I was leaving, and when I told him I was taking a flight back tomorrow he insisted that I stay a little longer."
General Sharon's Lubavitcher friends explained to him that the Rebbe doesn't say such things just out of politeness and insisted that he postpone his flight. The plane that Sharon was to have taken was hijacked to Libya. At a later date, another Israeli cabinet member, in private audience with the Rebbe, poised the obvious question. "If you knew," he asked the Rebbe, "why did you not report the matter to the authorities and attempt to circumvent the whole hijacking?" "Do you think I knew?" the Rebbe responded in a very serious tone. "It is not a matter of prophecy or knowing. It is simply that when I see someone standing before me, I am so completely obsessed with doing that person a favor -- that is why I say what I say."

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