[141] for those teachers are foolish who attempt to regulate their explanations not by a reference to the capacity of their pupils, but to their own superior ability, not being aware that there is a vast difference between making a display and giving a lesson. For he who is making a display, relying on the good fortune of his present way of proceeding, brings into sight, without any trouble, the works at which he has for a long while been labouring at home, like the works of painters or sculptors, seeking for praise from the multitude. But he who is endeavouring to teach others, like a good physician, has a regard not to the greatness of his own skill, but to the capacity of his patient who is to be healed; not thinking how much he can do by his art, for it is unspeakable how much this may be; but what the patient requires, aiming at moderation, and bringing forward what may improve him.