Then Moses set aside three cities across the Jordan to the east

Numbers 35:6
Six of the cities you give the Levites are to be appointed as cities of refuge, to which a manslayer may flee. In addition to these, give the Levites forty-two other cities.

Numbers 35:14
Select three cities across the Jordan and three in the land of Canaan as cities of refuge.

Deuteronomy 4:42
to which a manslayer could flee after killing his neighbor unintentionally without prior malice. To save one's own life, he could flee to one of these cities:

Deuteronomy 19:2
then you are to set apart for yourselves three cities within the land that the LORD your God is giving you to possess.

Joshua 20:2
"Tell the Israelites to designate the cities of refuge, as I instructed you through Moses,

Joshua 20:7
So they set apart Kedesh in Galilee in the hill country of Naphtali, Shechem in the hill country of Ephraim, and Kiriath-arba (that is, Hebron) in the hill country of Judah.

Then Moses severed three cities on this side Jordan toward the sun rise;