VATICAN CITY (CNS) -- A world that has become "heartless" and indifferent to greed and war, and a Catholic Church in need of revitalizing its missionary joy need to open themselves up to Christ's infinite love, Pope Francis wrote.

By contemplating Jesus' Sacred Heart, the faithful can be filled with the "living water that can heal the hurt we have caused, strengthen our ability to love and serve others, and inspire us to journey together toward a just, solidary and fraternal world," the pope wrote in his encyclical, "'Dilexit nos' ('He loved us'): on the Human and Divine Love of the Heart of Jesus Christ."

The Vatican released the 28,000-word text Oct. 24.

While it is the pope's fourth encyclical, he wrote that it is meant to be understood in tandem with his previous two encyclicals, "Laudato Si', on Care for Our Common Home" and "Fratelli Tutti, on Fraternity and Social Friendship."

"The present document can help us see that the teaching of the social encyclicals … is not unrelated to our encounter with the love of Jesus Christ," he wrote. "For it is by drinking of that same love that we become capable of forging bonds of fraternity, of recognizing the dignity of each human being, and of working together to care for our common home."

The pope had said in June, the month the church traditionally dedicates to the Sacred Heart of Jesus, that he was going to release a document in the fall on the devotion to "illuminate the path of ecclesial renewal, but also to say something significant to a world that seems to have lost its heart."

The encyclical includes numerous reflections from the Bible, previous magisterial texts and the writings of saints and his fellow Jesuits, to re-propose to the whole church the centuries-old devotion. Since 1899, there have been four papal encyclicals and numerous papal texts dedicated to the Sacred Heart -- a symbol of Jesus' infinite love, which moves the faithful to love one another.

"In the deepest fiber of our being, we were made to love and to be loved," the pope wrote.

However, he wrote, "when we witness the outbreak of new wars, with the complicity, tolerance or indifference of other countries, or petty power struggles over partisan interests, we may be tempted to conclude that our world is losing its heart."

"It is heartbreaking," he wrote, to see elderly women, who should be enjoying their golden years, experiencing the anguish, fear and outrage of war. "To see these elderly women weep, and not feel that this is something intolerable, is a sign of a world that has grown heartless."

"The most decisive question we can ask is, 'Do I have a heart?'" the pope wrote.

The human being is more than an instrument, a material body and a carrier of intelligence and reason, the pope wrote.

The human person also embodies spiritual, emotional, creative and affective dimensions that are often undervalued, neglected or squelched in today's world, he wrote. It is the heart that integrates all these dimensions that are so often fragmented or neglected.

The most precious treasures that animate and dwell in the human heart are often the simple and poignant moments in life: "How we first used a fork to seal the edges of the pies that we helped our mothers or grandmothers to make at home"; "a smile we elicited by telling a joke"; "the worms we collected in a shoebox"; and "a wish we made in plucking a daisy."

"All these little things, ordinary in themselves yet extraordinary for us, can never be captured by algorithms" and artificial intelligence, he wrote, and, in fact, "poetry and love are necessary to save our humanity," not just reason and technology.

At a Vatican news conference presenting the encyclical Oct. 24, Archbishop Bruno Forte of Chieti-Vasto, Italy, said the document is a "compendium" and the "key" to understanding Pope Francis' pontificate.

Some commentators criticize the pope for focusing too narrowly on "social" issues, the archbishop said. This encyclical explicitly presents the spiritual and theological foundation underlying the pope's message to the church and the world for the past 12 years -- that everything "springs from Christ and his love for all humanity."

Many saints and religious congregations have a special devotion to the Sacred Heart, including St. Ignatius of Loyola and the Society of Jesus, the religious order the saint co-founded and to which Pope Francis belonged.

St. Ignatius' spiritual exercises encourage people to "enter into the heart of Christ" to "enlarge our own hearts" and train them to "sense and savor" the Gospel message and "converse about it with the Lord," the pope wrote.

Christ's heart is aflame with infinite love, and Christ desires to be loved and consoled in return, the pope said, especially by loving and serving one's neighbors and those who are most marginalized.

Jesus associated with "the lowest ranks of society," he wrote, introducing the "great novelty of recognizing the dignity of every person, especially those who were considered 'unworthy.'"

"In union with Christ, amid the ruins we have left in this world by our sins, we are called to build a new civilization of love," the pope wrote. "That is what it means to make reparation as the heart of Christ would have us do."

"Amid the devastation wrought by evil, the heart of Christ desires that we cooperate with him in restoring goodness and beauty to our world," Pope Francis wrote.

The encyclical was published as members of the Synod of Bishops were wrapping up a multiyear process focused on fostering "a synodal Church: communion, participation and mission."

In his encyclical, the pope emphasized how only a deep and abiding love in the Lord can inspire and fuel Catholics to share the Gospel and God's love with the world.

Mission requires missionaries who are "enthralled by Christ" and are "impatient when time is wasted discussing secondary questions or concentrating on truths and rules because their greatest concern is to share what they have experienced," he wrote.

"They want others to perceive the goodness and beauty of the Beloved through their efforts, however inadequate they may be," he wrote.

The heart of Christ also frees Catholics from the problem of communities and pastors who are "excessively caught up in external activities, structural reforms that have little to do with the Gospel, obsessive reorganization plans, worldly projects, secular ways of thinking and mandatory programs," he wrote.

"The result is often a Christianity stripped of the tender consolations of faith, the joy of serving others, the fervor of personal commitment to mission, the beauty of knowing Christ and the profound gratitude born of the friendship he offers and the ultimate meaning he gives to our lives," he added.

Pope Francis invited Catholics to rediscover or strengthen their devotion to the Sacred Heart of Jesus and the practices connected with it, particularly Eucharistic adoration and receiving the Eucharist on the first Friday of each month.

This practice once served to remind the faithful that Communion was not a reward for the perfect, he wrote, but to renew people's confidence in the "merciful and ever-present love" of Christ in the Eucharist and his invitation "to union with him."

Today the First Fridays devotion, he wrote, can help counter "the frenetic pace of today's world and our obsession with free time, consumption and diversion, cell phones and social media (and) we forget to nourish our lives with the strength of the Eucharist."