Numbers 35:14-16

Amplified Bible

¹⁴ You shall provide three cities on this [east] side of the Jordan [River], and three [more] cities in the land of Canaan; they are to be the cities of refuge. ¹⁵ These six cities shall be a refuge for the Israelites and for the stranger and the resident alien among them; so that anyone who kills a person unintentionally may escape there.

¹⁶ ‘But if he struck ^[a]his victim down [intentionally] with an iron object so that he died, he is a murderer; the murderer shall certainly be put to death.