Jamieson-Fausset-Brown on Numbers 35:29
these things shall be for a statute of judgment unto you throughout your generations--The law of the blood-avenger, as thus established by divine authority, was a vast improvement on the ancient practice of Goelism. By the appointment of cities of refuge, the manslayer was saved, in the meantime, from the blind and impetuous fury of vindictive relatives; but he might be tried by the local court, and, if proved guilty on sufficient evidence, condemned and punished as a murderer, without the possibility of deliverance by any pecuniary satisfaction. The enactment of Moses, which was an adaptation to the character and usages of the Hebrew people, secured the double advantage of promoting the end…
Read the whole note in the consoleAdam Clarke on Numbers 35:30
But one witness shall not testify against any - This was a just and necessary provision. One may be mistaken, or so violently prejudiced as to impose even on his own judgment, or so wicked as to endeavor through malice to compass the life of his neighbor: but it is not likely that two or more should be of this kind; and even were they, their separate examination would lead to a discovery of the truth, and to their conviction.
John Gill on Numbers 35:30
Whoso killeth any person,.... Willingly, and through enmity and malice:
the murderer shall be put to death by the mouth of two witnesses; which is repeated partly to show, that this law concerning the cities of refuge was not designed to screen a murderer, who was guilty through malice prepense; and partly for the sake of what is added to it, that two witnesses are required in such a case, where a man's life is at stake, to prove the fact against him; which shows how careful the Lord is, and men should be, of the lives of his creatures, that no man suffer wrongfully; which is repeated again and again, that it might be observed, see Deuteronomy 17:6 but one witness shall not testify against…
Read the whole note in the consoleJohn Calvin on Numbers 35:9–end