There was a great court at Jerusalem called Beth Yaazek, where all witnesses (who could testify to the time of the appearance of the new moon) used to assemble, and where they were examined by the authorities. Grand feasts were prepared for them as an inducement to them to come (and give in their testimony). Formerly they did not move from the place they happened to be in when overtaken by the Sabbath, but Rabbon Gamliel the elder ordained that they might in that case move two thousand cubits either way.
Rosh Hashanah, fol. 21, col. 2.
He that is abroad (on the Sabbath) and does not know the limit of the Sabbath day's journey may walk two thousand moderate paces, and that is a Sabbath day's journey.
Eiruvin, fol. 42, col. 1.
Rabbon Gamliel had a hollow tube, through which, when he looked, he could distinguish a distance of two thousand cubits, whether by land or sea, By the same tube he could ascertain the depth of a valley or the height of a palm tree.
Ibid., fol. 43, col. 2.
He who observes carefully the precepts respecting fringes will, as a reward, have two thousand eight hundred slaves to wait upon him; for it is said (Zech. viii. 23), "Thus saith the Lord of hosts; In those days it shall come to pass that ten men shall take hold out of all languages of the nations, even shall take hold of the skirt of him that is a Jew, saying, We will go with you, for we have heard that God is with you."
Shabbath, fol. 32, col. 2.
Rashi's explanation of this matter is very simple. The merit of the fringes lies in their being duty attached to "the four quarters" or skirts of the garments (Deut. xxii. 12). There are seventy nations in the whole world, and ten of each nation will take hold of each corner of the garment, which gives 70 x 10 x 4 = 2800. Rabbi B'chai, commenting on Num. xv. 39, 40, repeats the same story almost word for word.
This passage (Zech. Viii. 23) has lately been construed by some into a prophecy of the recent Berlin Congress, and the ten men mentioned are found in the representatives of the contracting parties, i. e., England, France, Germany, Turkey, Russia, Austria, Italy, Greece, Roumania, and Servia.