The worst prison would be a closed heart. This statement is also attributed to others.

Darkness can only be scattered by light, hatred can only be conquered by love.

Stupidity is also a gift of God, but one mustn't misuse it.

War is a defeat for humanity.

Modern Society will find no solution to the ecological problem unless it takes a serious look at its lifestyles.

Faced with today's problems and disappointments, many people will try to escape from their responsibility. Escape in selfishness, escape in sexual pleasure, escape in drugs, escape in violence, escape in indifference and cynical attitudes. I propose to you the option of love, which is the opposite of escape. Said during his first visit to the US in 1979.

As the family goes, so goes the nation and so goes the whole world in which we live.

When you wonder about the mystery of yourself, look to Christ, who gives you the meaning of life. When you wonder what it means to be a mature person, look to Christ, who is the fulfillness of humanity. And when you wonder about your role in the future of the world look to Christ.

The future starts today, not tomorrow.

Science develops best when its concepts and conclusions are integrated into the broader human culture and its concerns for ultimate meaning and value. Scientists cannot, therefore, hold themselves entirely aloof from the sorts of issues dealt with by philosophers and theologians. By devoting to these issues something of the energy and care they give to their research in science, they can help others realize more fully the human potentialities of their discoveries. They can also come to appreciate for themselves that these discoveries cannot be a genuine substitute for knowledge of the truly ultimate. Science can purify religion from error and superstition; religion can purify science from idolatry and false absolutes. Each can draw the other into a wider world, a world in which both can flourish. Letter to the Reverend George V. Coyne, S.J., Director of the Vatican Observatory (1988-06-01).

The Jewish religion is not extrinsic to us but in a certain way intrinsic to our own religion. With Judaism, therefore, we have a relationship which we do not have with any other religion. You are our dearly beloved brothers, and, in a certain way, it can be said that you are our elder brothers. Visiting a Jewish synagogue in Rome. (1986)

War should belong to the tragic past, to history: it should find no place on humanity's agenda for the future.

Violence and war can never resolve the problems of men.

Humanity should question itself, once more, about the absurd and always unfair phenomenon of war, on whose stage of death and pain only remain standing the negotiating table that could and should have prevented it.

The great danger for family life, in the midst of any society whose idols are pleasure, comfort and independence, lies in the fact that people close their hearts and become selfish.

The historical experience of socialist countries has sadly demonstrated that collectivism does not do away with alienation but rather increases it, adding to it a lack of basic necessities and economic inefficiency.

Pervading nationalism imposes its dominion on man today in many different forms and with an aggressiveness that spares no one. The challenge that is already with us is the temptation to accept as true freedom what in reality is only a new form of slavery.

Man always travels along precipices. His truest obligation is to keep his balance.

God of our fathers, you chose Abraham and his descendants to bring your name to the nations: We are deeply saddened by the behavior of those who in the course of history have caused these children of yours to suffer, and, asking your forgiveness, we wish to commit ourselves to genuine brotherhood with the people of the covenant. Written prayer, placed by John Paul II into the "Wailing Wall" while visiting Jerusalem. (2000)

We are now standing in the face of the greatest historical confrontation humanity has ever experienced. I do not think the wide circle of the American Society, or the wide circle of the Christian Community realise this fully. We are now facing the final confrontation between the Church and the antichurch, between the Gospel and the antigospel, between Christ and the antichrist. This confrontation lies within the plans of Divine Providence. It is, therefore, in God's Plan, and it must be a trial which the Church must take up, and face courageously. From his farewell address in 1976, when as Cardinal of Krakow he attended the Eucharistic Congress in Philadelphia.