Numbers 35:10

10.Speak unto the children of Israel God appointed the cities of refuge, not only to make distinction between sills of malice and error, but also lest innocent blood should be rashly shed. Thus far we have seen how severely He would have murder punished: but, inasmuch as it would have been by no means just that he, who had not willfully but accidentally killed his neighbor, should be hurried away to the same punishment, to which willful murderers were subjected, an exception is added here, in order that he might escape who had killed another ignorantly, and unintentionally. Although, as has been said, God had a, further object, viz., lest murder upon murder should be committed, and the land should thus be polluted. Let us now examine the details in order. Although at the outset He only mentions the cities on the other side of Jordan, still we gather from what follows, that six cities were chosen for this purpose, of which three were on this side Jordan. He would have them so situated, that every part of the country should have one of them in its neighborhood, lest the exile of the unhappy persons, who were guiltless, should be rendered more painful by the distance they would have to travel. We have already briefly pointed out (52) that these cities were to be in the portions of Levi, in order that the dignity of the priesthood might the better protect the exiles, and also, because it was probable that there would be more prudence and serious feeling in the Levites, so that the refuge accorded to the innocent should not also shield the guilty.