The Most Sacred Heart of Jesus () is one of the most widely practised and well-known Catholic devotions, wherein the heart of Jesus Christ is viewed as a symbol of "God's boundless and passionate love for mankind". This devotion to Christ is predominantly used in the Catholic Church, followed by some high church Anglicans, and some Western Rite Orthodox. In the Latin Church, the liturgical Solemnity of the Most Sacred Heart of Jesus is celebrated on the third Friday after Pentecost. The 12 promises of the Most Sacred Heart of Jesus are also popular.

The devotion is especially concerned with what the Church deems to be the long-suffering love and compassion of the heart of Christ towards humanity. The popularization of this devotion in its modern form is derived from a Roman Catholic nun from France, Margaret Mary Alacoque, who said she learned the devotion from Jesus during a series of apparitions to her between 1673 and 1675,Jean Ladame, Marguerite–Marie, La sainte de Paray, Éditions Resiac, 1994 and later, in the 19th century, from the mystical revelations of another Catholic nun in Portugal, Mary of the Divine Heart, a religious sister of the congregation of the Good Shepherd, who requested in the name of Christ that Pope Leo XIII consecrate the entire world to the Sacred Heart of Jesus. Predecessors to the modern devotion arose unmistakably in the Middle Ages in various facets of Catholic mysticism, particularly with Gertrude the Great.

Description

The Sacred Heart is often depicted in Christian art as a flaming heart shining with divine light, pierced by the lance-wound, encircled by the crown of thorns, surmounted by a cross, and bleeding. Sometimes, the image is shown shining within the bosom of Christ with his wounded hands pointing at the heart. The wounds and crown of thorns allude to the manner of Christ's passion, while the flames represent a furnace of ardent love.Saint John Eudes:The sacred heart of Jesus

History of the devotion

Early devotion Historically, the devotion to the Sacred Heart is an outgrowth of devotion to what is believed to be Christ's sacred humanity.Hardon, John. Modern Catholic Dictionary During the first ten centuries of Christianity, there is nothing to indicate that any worship was rendered to the wounded Heart of Jesus. The revival of religious life and the zealous activity of Bernard of Clairvaux and Francis of Assisi in the twelfth and thirteenth centuries, together with the enthusiasm of the Crusaders returning from the Holy Land, gave a rise to devotion to the Passion of Jesus Christ and particularly to practices in honour of the Sacred Wounds.Holweck, Frederick. "The Five Sacred Wounds." The Catholic Encyclopedia. Vol. 15. New York: Robert Appleton Company, 1912. 1 Jun. 2013

Devotion to the Sacred Heart developed out of the devotion to the Holy Wounds, in particular to the Sacred Wound in the side of Jesus. The first indications of devotion to the Sacred Heart are found in the eleventh and twelfth centuries in the fervent atmosphere of the Benedictine or Cistercian monasteries."Heart of Jesus, Symbol of Love", Sisters of Carmel, Colorado Springs, CO It is impossible to say with certainty what were its first texts or who were its first devotees.

Bernard of Clairvaux ( 1153) said that the piercing of Christ's side revealed his goodness and the charity of his heart for humanity. The earliest known hymn to the Sacred Heart, , is believed to have been written by the Norbertine Herman Joseph (d. 1241) of Cologne, Germany. The hymn begins: "I hail Thee kingly Heart most high."

From the 13th to the 16th centuries, the devotion was propagated but it did not seem to have been embellished. It was everywhere practised by individuals and by different religious congregations, such as the Franciscans, Dominicans, and Carthusians. Among the Franciscans the devotion to the Sacred Heart of Jesus has its champions in Bonaventure (d. 1274) in his ("Mystic Vine") and John de la Verna. Bonaventure wrote: "Who is there who would not love this wounded heart? Who would not love in return Him, who loves so much?" It was, nevertheless, a private, individual devotion of the mystical order. Nothing of a general movement had been inaugurated, except for similarities found in the devotion to the Five Holy Wounds by the Franciscans, in which the wound in Jesus's heart figured most prominently.

Bonaventure's (a part from which is the reading for the Divine Office on the Solemnity of the Sacred Heart) refers to the heart as the fountain from which God's love poured into one's life:

Lutgarde According to Thomas Merton, Lutgarde (d. 1246), a Cistercian mystic of Aywieres, Belgium, was one of the great precursors of the devotion to the Sacred Heart of Jesus. A contemporary of Francis of Assisi, she "entered upon the mystical life with a vision of the pierced Heart of the Saviour, and had concluded her mystical espousals with the Incarnate Word by an exchange of hearts with Him."Merton, Thomas. What are These Wounds? the Life of a Cistercian Mystic, Saint Lutgarde of Aywieres, Clonmore and Reynolds Ltd., Dublin, 1948 Sources say that Christ came in a visitation to Lutgarde, offering her whatever gift of grace she should desire; she asked for a better grasp of Latin, that she might better understand the word of God and sing God's praise. Christ granted her request and Lutgarde's mind was flooded with the riches of psalms, antiphons, readings, and responsories. However, a painful emptiness persisted. She returned to Christ, asking to return his gift, and wondering if she might, just possibly, exchange it for another. "And for what would you exchange it?" Christ asked. "Lord, I would exchange it for your Heart." Christ then reached into Lutgarde and, removing her heart, replaced it with his own, at the same time hiding her heart within his breast.Kirby, Dom Mark Daniel. "Draw Me to Thy Piercèd Side", June 15, 2008, Silverstream Priory, Stamullen, County Meath, Ireland

Mechtilde Mechtilde of Helfta (d. 1298) became an ardent devotee and promoter of Jesus' heart after it was the subject of many of her visions. The idea of hearing the heartbeat of God was very important to medieval saints who nurtured devotion to the Sacred Heart. Mechtilde reported that Jesus appeared to her in a vision and commanded her to love him ardently, and to honor his sacred heart in the Blessed Sacrament as much as possible. He gave her his heart as a pledge of his love, as a place of refuge during her life and as her consolation at the hour of her death. From this time Mechtilde had an extraordinary devotion for the Sacred Heart, and said that if she had to write down all the favors and all the blessings which she had received by means of this devotion, a large book would not contain them.Croiset, S. J., John. The Devotion to the Sacred Heart, 1691

Gertrude

Gertrude the Great was an early devotee of the Sacred Heart of Jesus. Book 2 of the Herald of Divine Love () vividly describes Gertrude's visions, which show a considerable elaboration on the hitherto ill-defined veneration of Christ's heart. Bernard articulated this in his commentary on the Song of Songs. The women of Helfta – Gertrude foremost, who surely knew Bernard's commentary, and to a somewhat lesser extent the two Mechthildes – experienced this devotion centrally in their mystical visions.Jenkins, Eve B., "St Gertrude's Synecdoche: The Problem of Writing the Sacred Heart", Essays in Medieval Studies, Vol. 14, 1997, Illinois Medieval Association

In the 16th century, the devotion passed from the domain of mysticism into that of Christian asceticism. It was established as a devotion with prayers already formulated and special exercises, found in the writings of Lanspergius (d. 1539) of the Carthusians of Cologne, the Benedictine Louis de Blois (d. 1566) Abbot of Liessies in Hainaut, John of Avila (d. 1569), and Francis de Sales (d. 1622).

The historical record from that time shows an early bringing to light of the devotion. Ascetic writers spoke of it, especially those of the Society of Jesus (Jesuits). The image of the Sacred Heart of Jesus was everywhere in evidence, largely due to the Franciscan devotion to the Five Wounds and to the Jesuits placing the image on the title-page of their books and on the walls of their churches.

The first to establish the theological basis for the devotion was Polish Jesuit Kasper Drużbicki (1590–1662) in his book (The goal of hearts – Heart of Jesus). Not much later John Eudes wrote an office, and promoted a feast for it. John Eudes is regarded as "tireless apostle of the devotion of the Sacred Hearts", entitling him as 'Father', doctor and apostle of the liturgical cult of the hearts of Jesus and Mary.

Little by little, the devotion to the Sacred Hearts became distinct, and on 31 August 1670 the first feast of the Sacred Heart of Jesus was celebrated in the Grand Seminary of Rennes. Coutances followed suit on October 20, a day with which the Eudist feast was from then on to be connected. The feast soon spread to other dioceses, and the devotion was likewise adopted in various religious communities. It gradually came into contact with the devotion begun by Margaret Mary Alacoque at Paray-le-Monial, and the two merged.

Margaret Mary Alacoque

The most significant source for the devotion to the Sacred Heart in the form it is known today was Margaret Mary Alacoque (1647–1690), a nun of the Order of the Visitation of Holy Mary, who claimed to have received Sacred Heart revelations from Jesus Christ between 1673 and 1675 in the Burgundian French village of Paray-le-Monial.

The first apparition took place on 27 December 1673, the day of the feast of Saint John the Evangelist, during which Jesus allowed Margaret Mary to rest her head upon his heart, telling her that he wanted to make his love known to all mankind and that he had chosen her to spread the devotion to his Sacred Heart. Right after this, she had a vision of his heart with a crown of thorns, surrounded by flames and above which a cross was planted. This representation will become the popular image of the Sacred Heart which Margaret Mary used to propagate the devotion.

Between 1674 and 1675, other apparitions followed in which Jesus Christ revealed to Alacoque different forms of devotion to the Sacred Heart. The First Fridays Devotion, which is the reception of Holy Communion on nine first Fridays of each month, was revealed to her through a "Great Promise" of final penance granted to those who practice this act of reparation. Margaret Mary also said that she was instructed to spend an hour every Thursday night, from eleven to midnight, to pray and meditate on Jesus' agony in the Garden of Gethsemane. Her prayers intended to ask mercy for sinners as well as to make reparation for the abandonment Jesus felt from his apostles in the garden. This practice is now known as the "Holy Hour" and is also frequently performed during an hour of Eucharistic adoration.