As a human person he is entitled to the legal protection of his rights, and such protection must be effective, unbiased, and strictly just. To quote again Pope Pius XII: "In consequence of that juridical order willed by God, man has his own inalienable right to juridical security. To him is assigned a certain, well-defined sphere of law, immune from arbitrary attack."24Cf. Pius XII's broadcast message, Christmas 1942, AAS 35 (1943) 21.
The natural rights of which We have so far been speaking are inextricably bound up with as many duties, all applying to one and the same person. These rights and duties derive their origin, their sustenance, and their indestructibility from the natural law, which in conferring the one imposes the other.
Thus, for example, the right to live involves the duty to preserve one's life; the right to a decent standard of living, the duty to live in a becoming fashion; the right to be free to seek out the truth, the duty to devote oneself to an ever deeper and wider search for it. Reciprocity of Rights and Duties Between Persons