Numbers 35:11 in the World English Bible
then you shall appoint for yourselves cities to be cities of refuge for you, that the man slayer who kills any person unwittingly may flee there.
Context
10 Speak unto the children of Israel, and say unto them, When ye be come over Jordan into the land of Canaan;
11 Then ye shall appoint you cities to be cities of refuge for you; that the slayer may flee thither, which killeth any person at unawares.
12 And they shall be unto you cities for refuge from the avenger; that the manslayer die not, until he stand before the congregation in judgment.