Luke's nativity stories focus not on the movers, shakers and power centers of that ancient world but on ordinary people in a remote place. Those with rural roots or experience will recognize the phrase "back forty." Reference books define the back forty as a remote geographical area. Check with people who grew up on farms and you'll get more colorful definitions and descriptions. When the western lands were originally measured out they were divided into 160-acre tracts, four of forty each. The front forty faced the road and that is where the house stood. What about the back forty?
