Numbers 35:1-6

Cities for the Levites

1The Lord spoke to Moses in athe plains of Moab by the Jordan at Jericho, saying, 2 bCommand the people of Israel to give to the Levites some of the inheritance of their possession as cities for them to dwell in. And you shall give to the Levites pasturelands around the cities. 3The cities shall be theirs to dwell in, and their pasturelands shall be for their cattle and for their livestock and for all their beasts. 4The pasturelands of the cities, which you shall give to the Levites, shall reach from the wall of the city outward a thousand cubits
A  cubit was about 18 inches or 45 centimeters
all around.
5And you shall measure, outside the city, on the east side two thousand cubits, and on the south side two thousand cubits, and on the west side two thousand cubits, and on the north side two thousand cubits, the city being in the middle. This shall belong to them as pastureland for their cities.

6“The cities that you give to the Levites shall be dthe six cities of refuge, where you shall permit the manslayer to flee, and in addition to them you shall give forty-two cities.
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