Today throughout the Church is the feast of the Sacred Heart of Jesus. For a thorough treatment of the devotion you can read the article on it at the Catholic Encyclopedia, or for fully authoritative teaching on the Sacred Heart you can read the more recent 1956 encyclical Haurietis Aquas from the hand of Pope Pius XII.
Rather than duplicate what these two sources explain and teach, we might just focus on an essential truth of this devotion. The Sacred Heart of Jesus is very much his human heart. It is not so much that we worship the flesh and blood of his physical heart in itself, but rather what it symbolizes. In general use, we refer to the heart as the centre of our feeling and emotion, our inmost core, the place where we encounter God, and from which springs what love we can show to Him and to others. Much as when our physical heart ceases to function our body dies, so too this metaphorical (yet real!) heart is the life of our spirit. Jesus Christ, as a man as well as God, had such a human heart, both literally and metaphorically.
Thus, in a sense, the devotion to the Sacred Heart is a bold and audacious one. In adoring Jesus’ Sacred Heart we are adoring his humanity. Or to put it less disturbingly, we are adoring his Incarnation. For this real and metaphorical human heart of Jesus is ennobled and elevated (and we might even say completed) by its intimate and indivisible union with his divine nature, and thus with the most intimate life of God. In Jesus’ heart humanity and divinity encounter each other for us and for our salvation.
Jesus’ love for us, consummated in his self-sacrifice on the Cross (for no greater love has anyone than to lay down one’s life for one’s friends), springs from his Sacred yet human heart. At the same time, since it is the heart also of the incarnate Second Person of the Trinity, that self-giving love is transformed into something with divine power and effect. That is why Jesus’ death is not just the simple death of another man. His is a death that reveals a love that is totally other-centred: paradoxically, both for us and at the same time for the Father. For Jesus’ love for the Father cannot be separated from his love for humanity, as we see most clearly in John 17, where Christ prays to the Father that “all mine are thine, and thine are mine, and I am glorified in them” (v.10). Christ’s love for the Father reaches its zenith when he obeys the Father’s will that he should die for sinful humanity; Christ’s love for sinful humanity reaches its zenith by the very same obedience to the Father’s will.
So in Jesus’ Sacred Heart our Lord’s human love for us, and the suffering and anguish it entailed, meets, is accepted by and united with the divine love of God, the heart of the great Easter event of our salvation. In Jesus’ Sacred Heart the price of sin is paid and accepted. In his Heart, justice and mercy embrace and are satisfied.
Karl Rahner SJ, undeniably one of the theological greats of the twentieth century (flawed though he sometimes was), was a great apostle of devotion to the Sacred Heart. He reflected on this devotion in the wake of the Second Vatican Council, when traditional devotional practices were increasingly discarded or marginalized. While he accepted that the Church was an organic body that grew and developed, and that change in its devotional life was to be expected, he refused to accept that the devotion to the Sacred Heart was a devotion that could be discarded. In a time of a strong antiquarian spirit in the Church, which looked back to the primitive and very early Church for inspiration and discarded practices not found then, Rahner felt this spirit was sometimes nothing less than a blinkered attempt to return to the supposed golden days of the Church’s childhood, one that failed to realise that as the Church grew it also matured. The devotion to the Sacred Heart is for Rahner not something childish, but belonging to the maturity of the Church. And while some dismiss it as something not original in the Church’s life, equally to be resisted are those who, in their limited grasp of history, see the Sacred Heart devotion as something old-fashioned:
It is true that, despite its roots in John’s theology of the pierced side as the source of water and Spirit from which the Church is born, and despite the beginnings of an explicit devotion in the Middle Ages, this devotion is an historical event and an historical experience that were given to the Church only in the modern age. Naturally, this spiritual experience has its human-historical limitations that do not always have to remain the same. Christian faith and theological reflection have only slowly understood the proper nature of this spiritual experience, and what is properly meant when we speak of the heart of Jesus. We do not have to hold onto everything that has ever been said in the theology of the devotion to the Sacred Heart, in its efforts to assimilate spiritual experience. Nor are we supposed to hold onto the concrete devotional practices that were very much alive in former times. But when we consider the history of devotion to the Sacred Heart – not superficially, superciliously, or with scorn – and when we see the wealth of spiritual and charismatic experience it contained, when we bear in mind all the Church’s official declarations about it, when we remember the liturgical worship of the heart of Jesus in all its grandeur and impressiveness, we should not venture to say that we can simply forget about this devotion as something antiquated. If we were to think and to act that way, we would have to say that we were about to give up something that belongs to the Church’s past and therefore something of our own spiritual experience in the Church as well.
We may feel that we can easily forget about this past of our Church. In the laziness of our heart we are all too tempted to do so. But this does not prove that we are allowed to do so before God and considering our responsibility for the continuity of the Church’s history. Such a feeling must rather frighten us. We should face the question whether such a lazy slipping back into a primitive spirituality that wrongly appeals to ancient times, when the Sacred Heart devotion was unknown, is not something that we must overcome in a spirit of hopeful determination, if we do not want to be condemned by our past…
(Theological Investigations, 23, “Devotion to the Sacred Heart Today”)
The reason that Rahner cites for the continuing relevance of devotion to the Sacred Heart is that it both meets and answers as it corrects a tendency in “this naive era of optimism” to assume that everyone can be saved. Yet there is room for hope, and Rahner introduces a line of thought that would be taken up also by the equally great Hans Urs von Balthasar. Rahner continues:
[The Church] will never preach a theoretical doctrine of universal salvation, because, while carefully eschewing theoretical curiosity in eschatology, she will always humbly submit to the fear instilled by the threatening apocalyptic sermons of Jesus. But it seems to me that the Church has learned to have a universal hope for all and to forego making any theoretical and dogmatically binding statements about the actual occurrence of definitive damnation for a part of humankind.
First the Church must counter a false and worldly optimism which does not match the reality of modern existence:
Although those who continue to harbor great secular optimism are not forbidden to do so, this dawning time is one in which people are, to a large extent, running into limits they can no longer exceed. It is a time of crisis offering no possible alternatives, a time of resignation, of weariness, sterility, and exhaustion, a time in which individuals become ever more ignorant because they feel increasingly helpless before the enormity of what needs to be known. It is a time in which, despite all the talk of freedom and democracy, individuals are subject to ever more planning, and must be, because otherwise the enormous mass of people could not coexist, because otherwise people would exterminate a great part of the rest of the world by means of nuclear wars, just so that the survivors might have enough space in which to live. We are living in a time in which the anthropological sciences madly endeavor to smash people’s illusions, to unmask human beings as the mere product of fortuitous evolution, of the powers of their unconscious, of their drives, and of a society that does not know where it comes from and where it is going. Nature, exploited by humans, threatens them, and they themselves have learned how to bring about the universal suicide of humankind.
However, in acknowledging the true darkness of the world today, the Church nevertheless can speak with a balanced optimism, or rather with real hope, one that is founded on Christ:
It is into such a humanity that the Church enters with Jesus Christ’s message of universal salvation. It is because of Christ that we are emboldened to hope that the individual and humankind are advancing irreversibly, single-mindedly, toward eternal salvation in God, when they seem only to be plunging into the dark abyss of death. The Church keeps this hope, because she wishes to be faithful to the true God and the crucified Jesus. She holds on to it, while being fully aware of the dreadful, seemingly unabating wickedness of world history, which only discovers new and unprecedented ways of spending itself in hopeless guilt. In all this hopelessness for the present and the future, the Church remains the one that harbors universal hope, that even dares to hope more thoroughly than she did in the past.
This universal hope is not an easy painkiller in the wretchedness of our time, but, considered from the human point of view, it is an exorbitant demand. It is a modern form of the folly of the Cross, of hoping against all hope. It is a folly that sets God’s wisdom against the world’s wisdom, a wisdom in which the world begins to have doubts about itself. It is the courage to live that alone makes us really free; that, without uselessly counting the cost, teaches to let go and to give; that alone can prefer being to having and that can even love the enemy by whom one is killed.
So, living in a world in which a false optimism, or even escapism, is engendered by a vain faith in technology and secular democracy which blinds us to the very real dangers inherent in both, we are pointed by the Church to the Sacred Heart of Jesus as a true grounding for our faith and the source of a bold but well-founded hope. This hope is not just for ourselves but for all (for God wills that all men be saved and come to a knowledge of him [cf 1 Timothy 2:4]), and it is oriented to an end that is eternal rather than one centred on the here and now. The Sacred Heart is not a synonym for the Person of Jesus Christ; rather it refers to an encounter within Christ’s Person between the terminal cancer of human sinfulness and the overwhelming abundance of mercy which is God’s remedy for it. In the heart of Christ himself that battle has already been won. In pointing to his Sacred Heart as the foundation of our surest hope in sharing in Christ’s victory, the Church also points to that Heart as a revelation of God’s will for us, and so she recalls in the Liturgy today Jesus’ own words:
Come to me, all who labor and are heavy laden, and I will give you rest. Take my yoke upon you, and learn from me; for I am gentle and lowly in heart, and you will find rest for your souls. For my yoke is easy, and my burden is light. (Matthew 1:28-30)
Far from being childish or outmoded, devotion to the Sacred Heart of Jesus instead is a great weapon in the New Evangelization, as it confronts human hopelessness not with a vacuous optimism but with the assurance that God himself has shared the human condition in Jesus Christ and in him has transformed it into something wonderful; and as it invites people to have hope in him in whose heart that transformation has been achieved, for us and for our salvation.
Most Sacred Heart of Jesus, have mercy on us.