This is well written, not to mention the fact that it was written 100 years ago!
"Bullying is possibly the one original tendency that seems wholly bad. It is difficult to discern in it any element of good, and its uprooting, or the substitution of one of the kindlier, more helpful tendencies for it must be one of the duties of every teacher. Its persistence in adult life results in much harm and unhappiness. The brutality of the strong towards the weak, the misuse of power by governments, the refinement of cruelty shown in sarcasm and covered taunts, all find their explanation in this original tendency. Children cannot be held responsible for its existence in them, for it is part of their inherited equipment. They are not degenerate when they tease or bully,but for the good of society these tendencies must be modified and changed."
The book from which this is taken is titled The Psychology of Childhood.