The following is a quote about self-protection and the 17th century authors opinion about its morality. 

“….If the knife of the murderer is raised against thee or thine, 

and, through good providence and courage, 

thou slay him that would have slain thee, 

Thou losest not a tittle of thy integrity, having executed sudden justice; 

Still mayst thou walk among the blessed, 

though thy hands be red with blood.

 For thyself, thou art neither worse nor better; 

but thy fellows should count thee their creditor;

 

Thou hast manfully protected the right, 

and the right is stronger for thy deed.

 Also, in the rescuing of innocence, fear not to smite the ravisher.” 

Tupper 1700’s

 I like that.