In every sphere, "example is better than precept". That is, it is far more effective to show a learner how to do something by doing it before him correctly oneself, than merely to tell him what to do.
This is how the drill sergeant teaches raw recruits their military drill. He first goes through the various movements himself before them, sloping arms, presenting arms, trailing arms, fixing bayonets, and so on. His pupils watch his movements, and then try to copy them.
So in crafts, technical education is not picked up from books. The learner must go into the carpenter's shop, the smithy, the engineer's workroom or the mill, and watch and copy trained workmen as they actually do their tasks before him.
But it is in the moral sphere that example is so much more effective than precept, both for good and evil. Take the training of children by their parents. Children are very observant and are keen critics. They notice very quickly whether their father does himself what he teaches them. He teaches them it is wrong to tell lies, for example; but if he is himself untruthful, his teaching will have little effect. Children are great mimics; they will copy their parents. If the parents are really honest, truthful, kind and unselfish, or if they are dishonest, selfish and harsh, their children will imitate them.
To set children a good example is far more important than teaching them any number of fine moral maxims; and a bad example will do them far more harm than any amount of sound teaching will do them good.
Any man who sets himself up as a moral teacher must see to it that he does not undo all the good his teaching might affect, by a bad example. He must practice what he preaches, or his preaching will do more harm than good. Christ warned his disciples against the Scribes who said, "Do as we say, not as we do". Christ himself set the example, and said, "Follow me!" So the moral teacher must follow the example of Goldsmith's village Preacher:-
"He tried each art, reproved each dull delay,
Allured to brighter worlds, and led the way.”
The example of real goodness set before men by a really good man will do more for morality than hundreds of eloquent sermons or tons of moral advice.