The "Havamal" is full of teaching on this subject--the necessity of silence, the danger and the folly of reckless talk.

You all know the Japanese proverb that "the mouth is the front gate of all misfortune." The Norse poet puts the same truth into a grimmer shape: "The tongue works death to the head." Here are a number of sayings on this subject: He that is never silent talks much folly; a glib tongue, unless it be bridled, will often talk a man into trouble.
Do not speak three angry words with a worse man; for often the better man falls by the worse man's sword.
Smile thou in the face of the man thou trusteth not, and speak against thy mind.
This is of course a teaching of cunning; but it is the teaching, however immoral, that rules in English society to-day.

In the old Norse, however, there were many reasons for avoiding a quarrel whenever possible--reasons which must have existed also in feudal Japan.

A man might not care about losing his own life; but he had to be careful not to stir up a feud that might go on for a hundred years.

Although there was a great deal of killing, killing always remained a serious matter, because for every killing there had to be a vengeance.