First Law of Nature

"that every man, ought to endeavor peace, so far as he has hope of obtaining it; and when he cannot obtain it, that he may seek, and use, all helps, and advantages of war." (IP3 575ab)

Second Law of Nature

"that a man be willing, when others are so too, as far-forth, as for peace, and defence of himself he shall think it necessary, to lay down this right to all things; and be contented with so much liberty against other men, as he would allow other men against himself." (IP3 575b)