Bamidbar 35:14

את שלש הערים וגו׳ THE THREE CITIES [YE SHALL GIVE ON THIS SIDE OF THE JORDAN etc.] — Although in the land of Canaan there were nine tribes and here (on the east side of the Jordan) there were only two and a half, it (Scripture) gives them (the latter) the same number of cities of refuge, because in Gilead (on the east side) murderers were more numerous, as it is written, (Hosea 6:8): “Gilead is a city of them that work iniquity, it is covered with footprints of blood” (Makkot 9b; cf. Sifrei Bamidbar 160:2).

אֵ֣ת ׀ שְׁלֹ֣שׁ הֶעָרִ֗ים תִּתְּנוּ֙ מֵעֵ֣בֶר לַיַּרְדֵּ֔ן וְאֵת֙ שְׁלֹ֣שׁ הֶֽעָרִ֔ים תִּתְּנ֖וּ בְּאֶ֣רֶץ כְּנָ֑עַן עָרֵ֥י מִקְלָ֖ט תִּהְיֶֽינָה׃

You shall give three cities on this side of the Yarden, and three cities shall you give in the land of Kena῾an; cities of refuge shall they be.