[292] And rightly so; for it is well that in all activities, and most of all in the art of speaking, credit is won, not by gifts of fortune, but by efforts of study. For men who have been gifted with eloquence by nature and by fortune, are governed in what they say by chance, and not by any standard of what is best, whereas those who have gained this power by the study of philosophy and by the exercise of reason never speak without weighing their words, and so are less often in error as to a course of action.