Numbers 35:31-34

CLV(i) 31 Nor shall you take a sheltering ransom for the soul of the murderer, who stands condemned to die; for he shall be put to death, yea death. 32 And no sheltering ransom shall you take for one who had fled to his city of asylum only to return to dwell in the land before the death of the great priest. 33 You shall not pollute the land in which you are dwelling; for it is the blood that pollutes the land. As for the land, no shelter may be made for the blood which was shed on it save by the blood of him who shed it. 34 You shall not defile the land in which you are dwelling, in whose midst I am tabernacling, for I, Yahweh, am tabernacling in the midst of the sons of Israel.