The Pope's foreword to a youth catechism on marriage describes love as "a decision, a journey, and a lifelong covenant" — and opens with the Augustine motto on his own coat of arms.

Pope Leo XIV has written the foreword to a new edition of YouCat: Love Forever, a catechism aimed at young people preparing for marriage, due for release in November. The text offers the Pope's most extended public reflection to date on human love, marriage, and the vocation to which the Church calls young people.

The first edition of YouCat: Love Forever was published in May 2025, one week after the death of Pope Francis. This new edition features testimonies from young people in over 30 countries.

Leo opens with a disclosure that is also a self-portrait of sorts. Addressing young readers directly, he points to the burning heart pierced by an arrow on his papal coat of arms — the symbol of Saint Augustine — and the sentence it encodes: "Our hearts are restless until they rest in you, O God" (Confessions 1:1). This restlessness, Leo writes, is what lies beneath the longing for love: "Your heart longs for love. A love that is deep, self-sacrificing and enduring. This longing is no accident. It is a sign that you are made for love." He frames the desire not as a cultural construct or a psychological need but as evidence of a human nature oriented beyond itself — toward God, and toward another person as a path to God.

On the nature of love itself, the Pope draws a clear distinction between feeling and commitment. Love between a man and a woman "may strike the heart like an arrow — intensely and swiftly," he acknowledges — but it cannot remain there. "True love does not stop there. It is not merely a fleeting, briefly inflamed emotion. It is more. It is a deep commitment to the other, a decision, a journey and a covenant for life." He describes solid relationships as built on "mutual trust, on that 'forever' that is the beating heart of every vocation" — and characterized by a love that "asks first: 'How can I love as Christ loved?' and puts the question 'What do I get out of it?' last."

The Pope also reflects on the sacramental dimension of marriage, drawing on Augustine's Commentary on Psalm 127: "When a man and a woman give themselves wholly to one another in love, then God comes alive in their midst." He cites Augustine directly: "In him, who is one, we are one." Their fidelity, their forgiveness, their daily striving for what is good are, he writes, "a reflection of Christ's love for his Church." This love "is not perfect, but it grows in the light of faith" — and unlike human love clouded by selfish desires, it "is selfless, long-suffering, patient and possesses all the wonderful qualities that Paul lists in his Letter to the Corinthians" (cf. 1 Cor 13).

The most striking passage is the one Leo devotes to the cross. "We behold the most beautiful image of true love when we look at the cross of Jesus Christ" — confirmation that "he loves us so much that he was willing to die for us. This is the DNA of Christianity, the commandment of Christ."

He closes by encouraging young people not to fear the depth of the love to which they are called: it is "strong enough to overcome difficulties and great enough to sustain you throughout your entire life." The new edition of YouCat: Love Forever is, he says, an invitation to open one's heart "to a plan greater than any human dream."

YouCat — Youth Catechism of the Catholic Church — was first published in 2011 with a foreword by Pope Benedict XVI and has since been translated into dozens of languages. Various follow-up volumes have focused on particular elements of the faith. YouCat: Love Forever focuses specifically on the vocation to marriage and family life.