[66] And such an one before he practised was a pupil, having another to teach him; but when he became competent himself to guard what he had learnt, he then received the power and rank of a teacher, having appointed his brother, his own uttered discourse, to the ministration of teaching. For it is said that, "His brother shall minister;" [51] so that the mind of the good man is the guardian and steward of the doctrines of virtue. But his brother, that is to say, uttered discourse, shall minister instead of him, going through all the doctrines and speculations of wisdom to those who are desirous of instruction.