The Pope goes on to urge young people to respond to "spiritual joy" by not being afraid to risk their lives and by making "space for Jesus Christ and his Gospel."
This is particularly true, he says, if Christ is "calling you to the religious, monastic or missionary life or to the priesthood," since Jesus "fills with joy all those who respond to his invitation to leave everything to be with him" and "devote themselves with undivided heart to the service of others."
After experiencing the joy Jesus brings, everyone is called to love others, the Pope says.
"Joy is a net of love by which you can catch souls; God loves a cheerful giver. Whoever gives with joy gives more," he writes, quoting Blessed Teresa of Calcutta.
For a young person, this love should inform all aspects of their life so that they learn how love "means to be steadfast, reliable and faithful in commitments" particularly in work, study and friendships.
"Our friends expect us to be sincere, loyal and faithful because true love perseveres even in times of difficulty," he notes.
The Pope also prays that young people will lead lives "guided by a spirit of service and not by the pursuit of power, material success and money."
The temptation away from this is a present-day culture which often "pressures us to seek immediate goals, achievements and pleasures," fostering "fickleness more than perseverance, hard work and fidelity to commitments." This, he says, is nothing more than the promise of "false happiness."
"How many people are surrounded by material possessions yet their lives are filled with despair, sadness and emptiness! To have lasting joy we need to live in love and truth. We need to live in God."
This higher path, he warns, will not be without its occasional falls as "the experience of sin, which is a refusal to follow God and an affront to his friendship, brings gloom into our hearts."
Yet God in his mercy "never abandons us" and always offers the possibility of "being reconciled with him and experiencing the joy of his love which forgives and welcomes us back."
"Dear young people, have frequent recourse to the sacrament of Penance and Reconciliation! It is the sacrament of joy rediscovered," the Pope says.
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He brings his message to the youth to a close by offering some models of youthful holiness for them to emulate. First among them is the early 20th-century Italian student Blessed Pier Giorgio Frassati. Despite experiencing "many trials during his short life, including a romantic experience that left him deeply hurt," explains the Pope, Pier Giorgio always found the Christian life a joy, "even when it involves pain."
This experience of joy and pain is why it's an unfair and untrue to depict Christianity as "a way of life that stifles our freedom and goes against our desires for happiness and joy," Pope Benedict states.
On the contrary, Christians are "men and women who are truly happy because they know they are not alone" because God is "always holding them in his hand."
"It is up to you, young followers of Christ, to show the world that faith brings happiness and a joy which is true, full and enduring."
To read Pope Benedict's full message for World Youth Day 2012, please visit: http://www.catholicnewsagency.com/document.php?n=1061