Numbers 35:30-32

American Standard Version

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. ³¹ Moreover ye shall take no ransom for the life of a murderer, that is guilty of death; but he shall surely be put to death. ³² And ye shall take no ransom for him that is fled to his city of refuge, that he may come again to dwell in the land, until the death of the priest.