Thus, from something corporeal such as the Heart of Jesus Christ with its natural meaning, it is both lawful and fitting for us, supported by Christian faith, to mount not only to its love as perceived by the senses but also higher, to a consideration and adoration of the infused heavenly love; and finally, by a movement of the soul at once sweet and sublime, to reflection on, and adoration of, the divine love of the Word Incarnate.

We do so since, in accordance with the faith by which we believe that both natures – the human and the divine – are united in the Person of Christ, we can grasp in our minds those most intimate ties which unite the love of feeling of the physical Heart of Jesus with that twofold spiritual love, namely, the human and the divine love.

For these loves must be spoken of not only as existing side by side in the adorable Person of the divine Redeemer but also as being linked together by a natural bond insofar as the human love, including that of the feelings, is subject to the divine and, in due proportion, provides us with an image of the latter.

We do not pretend, however, that we must contemplate and adore in the Heart of Jesus what is called the formal image, that is to say, the perfect and absolute symbol of His divine love, for no created image is capable of adequately expressing the essence of this love.

But a Christian in paying honor along with the Church to the Heart of Jesus is adoring the symbol and, as it were, the visible sign of the divine charity which went so far as to love intensely, through the Heart of the Word made Flesh, the human race stained with so many sins.

It is therefore essential, at this point, in a doctrine of such importance and requiring such prudence that each one constantly hold that the truth of the natural symbol by which the physical Heart of Jesus is related to the Person of the Word, entirely depends upon the fundamental truth of the hypostatic union.

Should anyone declare this to be untrue he would be reviving false opinions, more than once condemned by the Church, for they are opposed to the oneness of the Person of Christ even though the two natures are each complete and distinct.

Once this essential truth has been established we understand that the Heart of Jesus is the heart of a divine Person, the Word Incarnate, and by it is represented and, as it were, placed before our gaze all the love with which He has embraced and even now embraces us.

Pius XII (1876-1958): Haurietis Aquas, 104-106.