Many traditions teach peace and nonviolence. Does this mean using lethal force to defend yourself isn’t approved by your tradition?

​The Bible says, “If possible, so far as it depends on you, live peaceably with all,” and that is to be our desire and our practice. There are times, though, when this isn’t possible, for example when someone is threatening our life or that of a loved one; at this time the preservation of the innocent party takes precedence. That is to say, yes, the use of lethal force to defend yourself is approved by the bible’s teaching.
This does not mean that we are allowed to seek revenge or take “an eye for an eye.” That aspect of justice and punishment is the responsibility of the government, not the individual; and, ultimately, vengeance belongs to the Lord, whose knowledge is perfect, and whose judgment is just.