Any of the Israelites or any foreigner residing among them who killed someone accidentally could flee to these designated cities and not be killed by the avenger of blood prior to standing trial before the assembly.
NIV
These cities were for all the Israelites and the stranger sojourning among them, that whoever killed a person unintentionally might flee there and not be slain by the avenger of blood until he had been tried before the congregation.
AMP
These were the cities appointed for all the children of Israel, and for the stranger that sojourneth among them, that whosoever killeth any person at unawares might flee thither, and not die by the hand of the avenger of blood, until he stood before the congregation.
KJV