Numbers 35:14-16

Young's Literal Translation

¹⁴ the three of the cities ye give beyond the Jordan, and the three of the cities ye give in the land of Canaan; cities of refuge they are.

¹⁵ To sons of Israel, and to a sojourner, and to a settler in their midst, are these six cities for a refuge, for the fleeing thither of any one smiting a person unawares.

¹⁶ `And if with an instrument of iron he hath smitten him, and he dieth, he [is] a murderer: the murderer is certainly put to death.