Midrasz do Liczb 35:6

(Fol. 9b) Our Rabbis were taught: Three cities did Moses separate on this side of the Jordan, and corresponding to them, Joshua separated in the land of Canaan, and they were right opposite one against the other, just as two rows in a vineyard. Namely (Josh. 20, 7) Hebron in Judah, opposite (Deut. 4, 43) Bezer in the wilderness; Shechem in the mountain of Ephraim, opposite Ramoth in Gilead; Kedesh in Galilea in the mountain of Naphthali, opposite Golan in Bashan. (Josh. 20, 7) And the three, i.e., it should be divided into three that there shall be the same distance from South Palestine to Hebron as from Hebron to Shechem; and from Hebron to Shechem as from the latter to Kedesh, and from Shechem to Kedesh as from the latter to North Palestine. How is it that three were needed on the other side of the Jordan, and only three for the whole land of Israel? Said Abaye: "In Gilead there were many murderers, (Fol. 10) as it is written (Hos. 6, 8) Gilead is a city of them that work iniquity, it is covered with footprints of blood." And R. Elazar explained the verse: "They followed up [their victims] to commit murder." Why were the cities on both sides of the Jordan far from the boundary, and the middle one near? Said Abaye: "Because Shechem was also full of murderers: as it is said (Ib., ib. 9) And as troops of robbers wait for a man, so doth the company of priests, they murder in the way toward Shechem." What is meant by the company of priests? Said R. Elazar: "They conjoined themselves to kill as the priests who would enjoin themselves to receive the heave-offerings from the barns." But were there not more cities of refuge? Behold there is (Num. 35, 6) And in addition to them shall ye give forty and two cities? Said Abaye: "The former protects the refugee in any instance, whether he is aware of that city being a place of refuge or not; while the latter accept him only when he is aware [of its protective power]." Was then the city of Hebron indeed a city of refuge? Does not the passage say (Jud. 1, 20) And they gave Hebron unto Kaleb as Moses ordered. Said Abaye: "It was only the suburb of it, as it is written (Josh. 21, 12) But the fields of the city, and the villages thereof, gave they to Caleb, the son of Jephunneh."