Reference for Eruvin 112:5

תניא אמר רבי אליעזר ברבי יוסי תחום ערי לוים אלפים אמה צא מהן אלף אמה מגרש נמצא מגרש רביע והשאר שדות וכרמים

It was taught: R'Eliezer son of R'Jose stated: The limit of the allotted land beyond the confines of the levitical cities<span class="x" onmousemove="('comment',' In addition to the cities themselves the Levites were allowed stretches of land around them for use as open spaces, fields and vineyards as will be specified below.');">¹⁴</span> was two thousand cubits.<span class="x" onmousemove="('comment',' In an outward direction round each city.');">¹⁵</span> Deducting from these<span class="x" onmousemove="('comment',' The 2000 cubits mentioned.');">¹⁶</span> an open space of one thousand cubits,<span class="x" onmousemove="('comment',' Immediately behind and around each city.');">¹⁷</span>

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