Deuteronomy 4:41
The Narrative Concerning Cities of Refuge
4:41 Then Moses selected three cities in the Transjordan, toward the east.
Deuteronomy 19:2
19:2 you must set apart for yourselves three cities
in the middle of your land that the
Lord your God is giving you as a possession.
Deuteronomy 19:7
19:7 Therefore, I am commanding you to set apart for yourselves three cities.