It was after the Egyptians had left the room, that Joseph made himself known unto his brethren. It was through closed doors that the risen Lord came to His disciples. If we are to enjoy communion with Him, the world must be shut out. "A garden inclosed is my sister, my spouse; a spring shut up, a fountain sealed." The name of Luz (separation) was changed to Bethel (House of God). Mere negative separation may be pharisaism; it must be unto God to really keep us from defilement.