Eiruvin 42 - 48
Let Him Come Today!
"Behold, I send you the prophet Eliyahu before the arrival of the great and awesome day of Hashem..." (Malachi 3:23)
This Divine promise that the prophet will appear as the herald of Mashiach a day before the Mashiach's arrival has an interesting condition built into it.
Israel has been guaranteed, say our Sages, that Eliyahu will not appear on the day preceding Shabbos or Yom Tov because of the problem this would cause (all Jews would abandon their Shabbas preparations to go and welcome the prophet - Rashi).
What about Mashiach himself? Won't his arrival on erev Shabbos create the same kind of problem? No, answer our Sages. With Mashiach's arrival, all the nations of the world will become subservient to the People of Israel (and there will be plenty of people to make the necessary preparations - Rashi).
There are many Talmudic and Midrashic references to the significance of Eliyahu's arrival. One of them has to do with the term teyku used by the gemara in declaring a halachic question unresolved. Tradition has it that teyku is an acronym for the words "tishbi yetaretz kushios u'boyos" - "Eliyahu the Tishbite will resolve all contradictions and unresolved questions." That great day when Eliyahu appears, all our questions will be answered.
Once, on erev Shabbos, a great Torah leader was overheard by his students praying for the immediate arrival of Eliyahu to announce the end of the long exile. "But Eliyahu is not scheduled to arrive on erev Shabbos?" they challenged him.
"We desperately need Eliyahu to arrive today," he explained. "But you have asked a good question. So when Eliyahu arrives, he'll answer your question along with all the others."
Secure Borders Then and Now
Our Sages gave a special dispensation for walking beyond the regular "techum" limit on Shabbos to a person who went beyond that limit in order to rescue a Jewish community from a military siege. This concept introduces a discussion of a fascinating chapter in Jewish history.
While David and his band of followers were fleeing the pursuing army of King Saul, David was informed that the city of Keilah was besieged by the Philistines who were looting the granaries of the Jewish residents (Shmuel I, 23:1). Although the combined danger of Saul's pursuit and the prospect of battling the Philistine forces meant a serious risk to life, this future king of Israel led his little army into the fray and rescued Keilah.
But if the Philistines were only interested in the grain, asks the gemara, what justified risking his own life and the lives of his soldiers? The halacha only sanctions military action against an enemy even on Shabbos when the enemy's intention is to kill, not when his objective is merely a monetary one.
Rabbi Dostai of Biri explains that Keilah was a city on the border between the territories of the Israelites and the Philistines. In regard to a border city, the halacha tells us that defensive military action may be taken even on Shabbos even if the invaders are only trying to plunder straw and hay (because the capture of such a strategic city exposes the entire nation to the danger of conquest - Rashi). Keilah's security, even if presently threatened for a monetary motive, was thus an issue which could affect the lives of the entire nation and therefore justified military action even on Shabbos.