George Adam Smith, the 19th century biblical scholar tells of traveling one day in the holy land and coming across a shepherd and his sheep. He fell into conversation with him and the man showed him the fold into which the sheep were led at night. It consisted of four walls, with a way in. Smith asked him, "This is where they go at night?" 

"Yes," said the shepherd, "and when they are in there, they are perfectly safe." 

"But there is no door," said Smith. 

"I am the door," said the shepherd. 

He was not a Christian man and wasn't speaking in the language of the New Testament. He was speaking from an Arab shepherd's viewpoint. Smith looked and him and asked, "What do you mean you are the door?" "When the light has gone," said the shepherd, "and all the sheep are inside, I lie in that open space, and no sheep ever goes out but across my body, and no wolf comes in unless he crosses my body; I am the door."