Numbers 35:6

For refuge, or, of receipt, or escape, or resort, to wit, for man-slayers; and these cities are assigned among the Levites, partly, because they might be presumed to be the most proper and impartial judges between man-slayers and wilful murderers; partly, because their presence, and counsel, and authority would more effectually bridle the passions of the avenger of blood who might pursue him thither; and partly, to signify that it is only in Christ (whom the Levitical priests did represent) that sinners find refuge and safety from the destroyer. The names of these cities, we have Deuteronomy 4:41,43 Jos 20:8. For the man-slayer, such as is here described, Numbers 35:11,15,22,23.