The love of Jesus for us all, which is symbolized by his Sacred Heart, is a basic theme of our Christian faith, and of our life of discipleship. That divine love made humanly manifest in our world through the sacrifice of Jesus on the cross is a consequence of the fact that “the Word became flesh, and dwelt among us.” (John 1:14) This theme of the Sacred Heart is rooted in the Bible and in the living tradition of the Church, and was developed over the centuries by many great saints and popes, enriching the spiritual life of countless Christians.
An important moment in the development of devotion to the Sacred Heart came with the great spiritual teacher and Doctor of the Church, Saint Francis de Sales (1567-1622). His masterpieces, the Introduction to the Devout Life and the Treatise on the Love of God continue to guide Christians to holiness, especially laypeople engaged in the duties of the secular world. Francis had great insights into the human heart, and famously gave this advice on preaching: “The lips speak to the ears, but heart speaks to heart.” That phrase, Cor ad Cor Loquitur, was later chosen as the motto of Saint John Henry Newman. In a world of upheaval and religious strife, Saint Francis de Sales was a model of gentleness, and always proclaimed the Faith with both clarity and charity. With Saint Jane Frances de Chantal (1572-1641), in 1610 he founded the Order of the Visitation nuns. The spirituality of the two founders emphasized the love of Jesus, especially as symbolized by the heart.
The saint most associated in recent centuries with the devotion to the Sacred Heart is Saint Margaret Mary Alacoque (1647-1690), a Visitation nun who between 1673 and 1675 received private revelations, visions during prayer of Our Lord, in which he speaks of prayer to the Sacred Heart.
Devotion to the Sacred Heart leads us to ponder the sacred humanity of Jesus, God with us. Using the universally accepted symbol of the heart as the sign of the center of who we are, this devotion focuses on Jesus as the man for others, who showed humans how, in a human way, to love as God loves, and to act as God wants us to act.
It is a devotion, not so much a liturgical prayer like the sacraments, though there is a liturgy for the Solemnity of the Sacred Heart. But the devotion to the Sacred Heart is more a way for each of us to intensely encounter Jesus in practices of prayer that move us to be better disciples, and to grow personally in holiness. Meditation upon the loving humanity of Jesus represented by the Sacred Heart, leads each of us to become more on fire for the Lord, to become not a superficial Christian, but a devoted Christian, a dedicated Christian, an intentional Christian committed to living out our baptismal mission to bring Christ into the world.
This devotion works in harmony with two other Christian devotions, also solidly founded on doctrine, which engage the whole person, emotionally as well as intellectually, and which impel the Christian to holiness: devotion to the real presence of Our Lord in the Eucharist, and devotion to Mary.
Devotion to the Sacred Heart is most fully expressed through adoration of Our Eucharistic Lord in the Holy Eucharist, and it is no accident that each year the Solemnity of the Sacred Heart occurs on the Friday following the Solemnity of Corpus Christi. Devotion to the Sacred Heart has also always been closely linked to devotion to the Immaculate Heart of Mary. All three of these are doctrinal devotions, intimate experiences of personal prayer which are founded on the objective doctrinal fact of who God is and how God acts among us. All three are rooted in the incarnation, for God came among us by being born as one of us through Mary, and the night before he offered himself for us on the cross, on that Good Friday of the Sacred Heart, he gave us the sacramental way to be joined to him down through the ages in the Holy Eucharist.
The great English spiritual writer, Msgr. Ronald Knox, sums up the breadth of the meaning of devotion to the Sacred Heart as an expression of our personal experience of the Lord whom we encounter in the Gospels: “The Sacred Heart is the treasury of all those splendid qualities with which a perfect life was lived; it is the repository of all those noble thoughts which mankind still venerates in the gospels. It was the Sacred Heart that burned with anger when the traders were driven out of the temple; it was the Sacred Heart that loved the rich young man, yet would not spare him; it was the Sacred Heart that defied Pilate in his own judgment-hall. It is strong and stern and enduring; it hates prevarications and pretences. The perfect flowering of a human life, not on this occasion or that, but all through, all the time, the utter sacrifice of a human will – that is what the Sacred Heart means, and there is no picture, no statue on earth that can portray its infinite beauty.” (Ronald Knox, “The Heart of Christ,” in Pastoral and Occasional Sermons, Ignatius Press: San Francisco, 2002, p. 488.) Although the heart is usually seen mainly as the sign of tender affectionate love – and that tender love of Jesus for us is indeed our consolation in our struggles – Msgr. Knox reminds us here of another dimension of the symbol of the heart, also represented in the Sacred Heart: it is a sign of having the courageous heart to fight against whatever is evil. Both Christian Social Justice and Christian charity come from the Sacred Heart.
The doctrinal and spiritual foundations of the devotion to the Sacred Heart are found in Scripture, but it only gradually developed into its present form. For a most thorough study of that development, and of the theology and history of devotion to the Sacred Heart, I highly recommend the excellent book by Timothy O’Donnell, Heart of the Redeemer: An Apologia for the Contemporary and Perennial Value of the Devotion to the Sacred Heart of Jesus, San Francisco: Ignatius Press, 2018.