Final answer:
Luke 2:4 refers to Bethlehem as another name for the 'city of David,' which is significant in both Judaism and Christianity.
Step-by-step explanation:
According to Luke 2:4, another name for the "city of David" is Bethlehem. This city has significant historical and religious importance. King David was born in Bethlehem and later became the ruler of Israel after Saul. These events laid the foundation for the city's alternate name. Moreover, Bethlehem is also where Jesus was born, which later fueled Christian pilgrimage to the region. The historical and religious narratives surrounding the city highlight its importance to both Judaism and Christianity.