....What are the causes of the lack of peace in today’s world? As Pope John Paul II tells us in his message for the World Day of Peace: “Violence and injustice have deep roots in the heart of each person, of each one of us.” Christ himself told us:“For out of the heart come evil thoughts, murder, adultery, fornication, theft, false witness, slander”—all the disorders men are capable of committing against God, against their brothers and sisters and against themselves, causing in the depths of their hearts a wound, a deep bitterness, a lack of peace that always affects society. But it is also from the human heart, from its immense capacity for love and self-sacrifice, that sentiments of fraternity and deeds of service to others can arise, made fruitful by Christ’s grace. This gives rise, as it were, to “a river of peace” that helps to build up a more just world, in which peace holds sway and imbues all the structures of society.
If you want—since you want—to be instruments of peace, “sowers of peace and joy along all the pathways of the world,” as Saint Josemaria Escriva liked to say, you need to have a great storehouse of peace in your heart. Then, from your abundance, you can give this peace to other men and women, beginning with those closest to you: your relatives, friends, colleagues and acquaintances. With words of John Paul II, I remind you that “the future of peace lies in your hearts.”
In this great endeavor to sow peace generously, you can’t be content with simply good desires. “This desire should lead to a firm moral conviction that encompasses the entire gamut of human problems and builds upon values that have been deeply assimilated. The world needs young people who have drunk deeply at the sources of the truth. You need to listen to the truth, and therefore you need a clean heart. You need to understand it, and therefore you need humility. You need to surrender yourselves to it and share it, and therefore you need the strength to resist the temptations to pride, self-sufficiency, and manipulation. You need to forge in your heart a deep sense of responsibility.”
These words of John Paul II are a call to undertake with determination, relying on God’s strength, the great task of constructing peace. This effort begins when each person fights against the disordered tendencies that nest in the human heart—the bitter fruit of original sin and personal sins. For “peace is something closely related to war. Peace is a consequence of victory. Peace demands of me”—of each man and woman—“a continual struggle. Without a struggle I will never have peace.”
In his apostolic letter for the International Youth Year, John Paul II urges you to seek strength in the Word of Christ, in prayer, in frequenting the sacraments. Thus you will be “strong for the struggle: not for the struggle of one against another in the name of some ideology or practice separated from the very roots of the Gospel, but strong for the struggle against evil, against the real evil: against everything that offends God, against every injustice and exploitation, against every falsehood and deceit, against everything that insults and humiliates, against everything that profanes human society and human relationships, against every crime against life: against every sin.”
This battle will last our entire life. “Man’s life on earth is warfare,” we read in the book of Job. Don’t think, then, that with the passage of the years the urgency for this interior struggle will lessen. God does not want for his children the false tranquility of the comfort-seekers, of the selfish, nor of the cowards. Human life unfolds on the great stage of the world and, as an early Father of the Church writes, “the eyes of the public are upon you. And not only the eyes of other men and women, but the multitude of angels witness your struggle … and the Lord of the angels presides over the battle.” Christ is pleased with your personal effort when you strive to follow Him, when you try to imitate Him despite each human being’s weaknesses. “In the Olympic games,” Saint John Chrysostom continues, “the referee stands in the middle of the two adversaries, without favoring either one, waiting for the outcome. He stands between the two combatants because his attitude is neutral. But in our combat with the devil, Christ isn’t indifferent. He is entirely on our side.”
Faced with our falls and sins, divine mercy comes to meet us, especially in the Sacrament of Penance. Have recourse to Confession as often as necessary, in order to cleanse yourself of sin and recover God’s grace, and thus be able to receive the Holy Eucharist, containing“the entire spiritual good of the Church, that is, Christ himself, our Pasch and Living Bread, by the action of the Holy Spirit through his very flesh vital and vitalizing, giving life to men.” Also have recourse to the Sacrament of Penance, doing so frequently, when you aren’t aware of grave sin in your soul, because in Confession your soul will receive the strength needed to joyfully fight the battles of peace, for the glory of God and the salvation of souls….
I invite you to place yourselves before Christ and dialogue sincerely with Him, without fearing what He may ask of you. When that young man with a deep unrest in his heart asked our Lord, “Teacher, what good deed must I do, to have eternal life?”, Jesus replied:“keep the commandments.” This is the first demand that Jesus addresses to everyone without exception. And then He added: “If you would be perfect, go, sell what you possess and give to the poor, and you will have treasure in heaven; and come, follow me.” That young fellow didn’t want to respond to God’s call, and he went away sad, because “sadness is the end product of selfishness;” it is the ally of the devil.
May this not happen to any of you. With words of John Paul II, I tell you: “if such a call comes into your heart, do not silence it! Let it develop into the maturity of a vocation! Respond to it through prayer and fidelity to the commandments! For ‘the harvest is plentiful’ and there is an enormous need for many to be reached by Christ’s call ‘Follow me,’ … along all the different paths taken by the disciples of the divine Redeemer.”
Link to entire homily in Spanish
 Pope John Paul II, Message for World Day of Peace, 1984, no. 1.
 Mt 15:19.
 Is 66:12.
 Pope John Paul II, Message for World Day of Peace, 1984, no. 3.
 Pope John Paul II, Message for World Day of Peace, 1984, no. 10.
 Saint Josemaria Escriva, The Way, no. 308.
 John Paul II, Apostolic Letter Dilecti Amici on the occasion of the International Youth Year, March 31, 1985, no. 15.
 Job 7:1.
 Saint John Chrysostom, Instruction to Catechumens III, 8.
 Ibid., 9.
 Vatican II, Decree Presbyterorum Ordinis, no. 5.
 Mt 19:16-17.
 Mt 19:21.
 Saint Josemaria Escriva, Friends of God, no. 92.
 John Paul II, Apostolic Letter Dilecti Amici on the occasion of the International Youth Year, March 31, 1985, nos. 8-9.