"Pacem in Terris (Peace on Earth) was a papal encyclical issued by Pope John XXIII in 1963. It remains one of the most famous of 20th century encyclicals and established principles that featured in some of the documents of the Second Vatican Council and of later popes.
Pacem in terris was the first encyclical that the Pope did not address to the Catholic faithful only, but also to "all men of good will".
In this work, John XXIII reacted to the then political situation in the middle of the Cold War. The "peace encyclical" was issued only two years after the erection of the Berlin Wall and only a few months after the Cuban Missile Crisis.
The Pope explains in this encyclical that conflicts "should not be resolved by recourse to arms, but rather by negotiation." He further emphasizes the importance of respect of human rights as an essential consequence of the Christian understanding of men. He clearly establishes, ...'That every man has the right to life, to bodily integrity, and to the means which are suitable for the proper development of life'..."
"The true and solid peace of nations consists not in equality of arms but in mutual trust alone."
Pope John XXIII (1881-1963). Pacem in Terris (On Establishing Universal Peace in Truth, Justice, Charity and Liberty), 113, 11 April 1963
Peace to all nations!