653. Everyone knows that a lamb can only act like a lamb, and a sheep only like a sheep; while on the other hand a wolf can act only like a wolf, and a tiger like a tiger. If these beasts were put together, would not the wolf devour the lamb, and the tiger the sheep? Consequently there are shepherds to guard them. Everyone knows that a spring of sweet water cannot from its vein bring forth bitter waters, and that a good tree cannot bring forth evil fruit, that a vine cannot prick like a thorn, a lily sting like a nettle, or a hyacinth wound like a thistle; or the reverse. These evil plants, therefore, are rooted out of fields, vineyards, and gardens, gathered into bundles, and thrown into the fire. So it is with the wicked pouring into the spiritual world, according to the Lord's words (Matt. 13:30; John 15:6). The Lord also said to the Jews, Ye offspring of vipers, how can ye being evil speak good things? A good man out of the good treasure of the heart bringeth forth good things; and an evil man out of the evil treasure bringeth forth evil things (Matt. 12:34-35).