They lie, because they fear to tell the truth, which is a thing that requires a good deal of moral courage sometimes.

They are apt to be revengeful, too, because they resent other people's superiority to themselves, and are not strong enough in manliness to be generous.

They seek revenge for petty wrongs, real or imaginary, in sly, sneaking, cowardly ways because--well because they are cowards.
Jake Elliott was a boy of this sort.

He was always a bully, and people who imagined that courage is best shown by fighting and blustering, thought Jake a very brave fellow.

If they could have known him somewhat better, they would have discovered that all his fighting was done merely to conceal the fact that he was afraid to fight.