Boyd’s Bible Dictionary:
(place for citizens). Cain and Nimrod city-builders (Gen. 4:17; 10:9-11). “Fenced cities” fortified cities (2 Kings 10:2; Isa. 26:1). “City of David,” Jerusalem, Bethlehem (1 Chron. 11:5; Luke 2:11). “City of God,” Jerusalem (Psa. 46:4; Neh. 11:1). “Cities of Refuge” six in number (Deut. 19:7-9; Num. 35:6-15).