by Jhon Locke (1690)

And hence it is that he who attempts to get another man into his absolute power does thereby put himself into a state of war with him; it being to be understood as a declaration of a design upon his life. For I have reason to conclude that he who would get me into his power without my consent would use me as he pleased when he had got me there, and destroy me too when he had a fancy to it; for nobody can desire to have me in his absolute power unless it be to compel me by force to that which is against the right of my freedom- i.e. make me a slave. To be free from such force is the only security of my preservation, and reason bids me look on him as an enemy to my preservation who would take away that freedom which is the fence to it; so that he who makes an attempt to enslave me thereby puts himself into a state of war with me. He that in the state of Nature would take away the freedom that belongs to any one in that state must necessarily be supposed to have a design to take away everything else, that freedom being the foundation of all the rest; as he that in the state of society would take away the freedom belonging to those of that society or commonwealth must be supposed to design to take away from them everything else, and so be looked on as in a state of war.
This makes it lawful for a man to kill a thief who has not in the least hurt him, nor declared any design upon his life, any farther than by the use of force, so to get him in his power as to take away his money, or what he pleases, from him; because using force, where he has no right to get me into his power, let his pretence be what it will, I have no reason to suppose that he who would take away my liberty would not, when he had me in his power, take away everything else. And, therefore, it is lawful for me to treat him as one who has put himself into a state of war with me- i.e., kill him if I can; for to that hazard does he justly expose himself whoever introduces a state of war, and is aggressor in it.