In a previous article, I suggested that the ruling descendants of David had migrated from Babylon to Nazareth. It is also possible that some of the descendants of David first moved to Bethlehem—David’s original home town—and then later migrated to Nazareth, perhaps joining other family members who had come from Babylon. Or perhaps they had all come, more recently, from Bethlehem.
When Joseph and Mary traveled to Bethlehem for a census (Luke 2:1), it is unlikely that they returned to Bethlehem simply because David had been born there a full thousand years earlier. Luke’s brief summary for the reason of their journey to Bethlehem is just that: a brief summary of what might otherwise be an involved (and tedious) explanation.