STEPHEN FARRELL  SEEN from the air, the fragility of humanity as it must have been in the Holy Land in centuries past is plain to see - ancient monasteries clinging to precipices, tiny fishing boats on the Sea of Galilee, deserts gnawing at the edges of towns. For the Christian faithful, the Biblical journey and legacy of Jesus are written in stonework and monuments across the landscape, straddling modern political faultlines. But modern pandemics, like ancient plagues, are no respecters of political and belief systems. For a year the Christian sites of the Holy Land, like the sacred places of…