(Devarim 19:2) "Three cities": of average size, not very small and not very large. "shall you set aside for yourself": and not for others (i.e., gentiles). "in the midst of your land": and not in a border city. "which the L-rd your G-d gives you to inherit": after you conquer and inherit it. ( Ibid . 3) "Prepare for yourself the way": Make stations leading into them. "and divide in thirds the border of your land': They (the cities of refuge) are not to be (indiscriminately) scattered, but aligned (with other such cities) by threes. "that the L-rd your G-d shall cause you to inherit": to include (the cities of refuge) across the Jordan (aligned) like two rows in a vineyard. "that every slayer may flee there" — even the high-priest, (though he, of course, cannot leave the city of refuge, as all others do, with the death of the high-priest).
Sifrei Devarim 180
Tap any verse to see what it echoes — and start a chain or echo from it.