John Calvin Commentary Numbers 35:30

"Whoso killeth any person, the murderer shall be slain at the mouth of witnesses: but one witness shall not testify against any person that he die." — Numbers 35:30 (ASV)

Whoever kills any person—He now returns to willful murderers, whom He will not spare, yet who are not to be handed over for punishment unless convicted by legal evidence.

Literally, the text states, Whoever strikes a soul, by the testimony of witnesses the slayer shall be put to death. This sentence is obscure due to its brevity, unless a noun is supplied before the second verb; this noun could refer to either the judges or the accuser.

In substance, however, there is no ambiguity: namely, that no one should be condemned unless lawfully convicted.

Moreover, He declares that one witness is insufficient, since it would be most unjust for a person’s life to be dependent on a single individual's testimony.

I have already cited a similar passage,⁵⁸ in which Moses instructed that no capital cases were to be decided except by the testimony of two or three witnesses; and because such declarations have general application, I have intentionally discussed them separately.

Now again, in referring to the condemnation of murderers, He takes the opportunity to state that two witnesses are required, since nothing is more likely to occur than the innocent being overwhelmed by slander and perjury if conviction depended on the testimony of any single individual.

But, while sure proof is required for guilt to be punished, so, when the murder is proven, God sternly requires and commands that it must not go unpunished.

He expressly forbids that the right of refuge should be purchasable, since otherwise it would have been in danger of becoming a shield for many crimes.

Therefore, when He forbids compensation to be accepted from anyone who would flee to a city of refuge, His purpose is that no one should enjoy this benefit until his innocence is fully established, lest the mercy by which the innocent were helped should become susceptible to bribery.

⁵⁸Deuteronomy 17:6. See . See ante, , p. 45..