Deuteronomy 19:4

4 This is the rule concerning anyone who kills a person and flees there for safety—anyone who kills a neighbor unintentionally, without malice aforethought.

Read Deuteronomy 19:4 Using Other Translations

And this is the case of the slayer, which shall flee thither, that he may live: Whoso killeth his neighbour ignorantly, whom he hated not in time past;
"This is the provision for the manslayer, who by fleeing there may save his life. If anyone kills his neighbor unintentionally without having hated him in the past--
“If someone kills another person unintentionally, without previous hostility, the slayer may flee to any of these cities to live in safety.