Numbers 35:30-32

Amplified Bible

³⁰ ‘If anyone kills a person [intentionally], the murderer shall be put to death on the testimony of [two or more] witnesses; but no one shall be put to death on the testimony of [only] one witness. ³¹ Moreover, you shall not accept a ransom [in exchange] for the life of a murderer guilty and sentenced to death; but he shall certainly be put to death. ³² You shall not accept a ransom for him who has escaped to his city of refuge, so that he may return to live in his [own] land before the death of the high priest.