Therefore my immediate impression of the walls and gates was not contradicted by my consciousness of what came before and what came after that medieval period. It remained primarily a thing of walls and gates; a thing which the modern world does not perhaps understand so well as the medieval world. There is involved in it all that idea of definition which those who do not like it are fond of describing as dogma. A wall is like rule; and the gates are like the exceptions that prove the rule. The man making it has to decide where his rule will run and where his exception shall stand. He cannot have a city that is all gates any more than a house that is all windows; nor is it possible to have a law that consists entirely of liberties. The ancient races and religions that contended for this city agreed with each other in this, when they differed about everything else. It was true of practically all of them that when they built a city they built a citadel. That is, whatever strange thing they may have made, they regarded it as something to be defined and to be defended. And from this standpoint the holy city was a happy city; it had no suburbs. That is to say, there are all sorts of buildings outside the wall; but they are outside the wall. Everybody is conscious of being inside or outside a boundary; but it is the whole character of the true suburbs which grow round our great industrial towns that they grow, as it were, unconsciously and blindly, like grass that covers up a boundary line traced on the earth. This indefinite expansion is controlled neither by the soul of the city from within, nor by the resistance of the lands round about. It destroys at once the dignity of a town and the freedom of a countryside. The citizens are too new and numerous for citizenship; yet they never learn what there is to be learned of the ancient traditions of agriculture. The first sight of the sharp outline of Jerusalem is like a memory of the older types of limitation and liberty. Happy is the city that has a wall; and happier still if it is a precipice.