Everyone in this world can be a teacher, but not a real teacher. A real teacher is the one who always teaches himself, and the more he teaches himself, the more he finds that there is so much to be taught. This self has so many lacks that the whole lifetime is not enough to teach it and the more the self learns, the more it overlooks the evil in others. It does not mean that the evil is not in the others, it only means that one finds that the enemy whom one was seeing outwardly is in oneself. And the worst enemy whom one was faced with in the outer life, one finds in one's own heart. It makes one feel humiliated, but it teaches the true lesson: to find oneself having the same element which one wishes to resist in another.