But even His parables might be turned to an evil use. It might be supposed that we can only reach the kingdom of heaven through the forms of earth; that they are not the likenesses of the invisible substances, but that the invisible substances are the likenesses of them. This danger is of such continual recurrence, it belongs so essentially to the idolatrous nature which is in us all, that it must have exhibited itself in the Christian Church before St. John wrote. Long allegories--which seem invented rather to hide the truth from common eyes than to bring it forth that it might be a possession for the wayfarer--began to be produced immediately after the apostolical age, if not within it. Nothing like them is to be found in this Gospel. Those parts of our Lord's teaching in which the parable was not used are brought into most prominence. Yet the parable is justified; all His acts are shown to be signs. And a proverb (παροιμία) is introduced here and there, which enables us to understand in what the worth of these natural likenesses consists, and how much the divine art which draws out the spiritual truth that is latent in them differs from the elaborate artifice of the allegorizer. '_Then said Jesus unto them again, Verily, verily, I say unto you, I am the door of the sheep. All that ever came before me are thieves and robbers: but the sheep did not hear them. I am the door; by me if any man enter in, he shall be saved, and shall go in and out, and find pasture. The thief cometh not, but for to steal, and to kill, and to destroy: I am come that they might have life, and that they might have it more abundantly._'