The Holy Spirit is wont to describe many things with few words. Wishing to praise the principal faculties of the body and soul of His Spouse, the Blessed Virgin Mary, and to exalt the merits of her Heart, He uses very few words, which nevertheless contain many meanings. What does He say? How does He praise Mary, the sovereign of hearts? He utters only three words: Quod intrinsecus latet (Song 4:1,3 what is hid within). But these three words encompass all the great and admirable utterances that can be said or thought of her royal Heart; they reveal to us that it is a treasure hidden from the most enlightened eyes of heaven and earth, a treasure so filled with celestial riches that God alone can have a perfect knowledge of its wonders.
Notice that the Holy Spirit pronounces these words not only once, but twice in the same chapter. He does this in order to impress them more strongly on our minds and to oblige us to consider them with greater attention, as well as to manifest to us both the corporeal heart of the Queen of Heaven…and her spiritual heart, of which I shall speak now.
What is the spiritual heart? In order to understand it, we must remember that, although the soul is essentially one, it can nevertheless be considered as having a threefold life.
The first and lowest life is that of the vegetative soul, which is similar in nature to that of plants, for the soul in this state has no other function than to nourish and sustain the body. The second is the sensitive life, which we have in common with animals. The third is the intellectual life, like that of angels, comprising the intellectual memory, the intellect proper and the will, together with the highest part of the mind, which theologians call the point, the summit or the eminence of the spirit. This last power is led not by the light of complex reasoning, but by a clear intuition of the intellect and a simple movement of the will whereby the soul submits to the truth and the will of God.
It is this third life called spirit, the mental, superior part of the soul, which renders us like the angels and carries with it in its natural state the image of God and in the state of grace, a participation of the divine nature.
This intellectual part is the heart and the noblest portion of the soul, for, first, it is the principle of the natural life of the rational soul, which consists in the knowledge it can obtain of supreme truth with the aid of the natural light of its intelligence, and in its natural love for sovereign goodness. Animated by the spirit of faith and grace, it becomes the principle of the supernatural life of the soul, which knows God by celestial light and loves Him with supernatural love. “This is eternal life: That they may know thee, the only true God” (Jn 17:3).
Secondly, this intellectual part is the heart of the soul, because in it is centered the will, the faculty and capacity of loving, but in a manner much more spiritual and noble and exalted and with a love incomparably more excellent, more lively, more active, more solid and durable than the love which proceeds from the sensitive and corporeal heart.
The will, enlightened by the light of the intellect and the torch of faith, is the principle of this love. When it is led only by the light of human reason and acts only in virtue of its natural capacities, the will produces only a human and natural love incapable of uniting the soul to God. But when it follows the torch of faith, and is moved by the impulses of the spirit of grace, it becomes the source of a supernatural and divine love, which makes the soul worthy of God.
Thirdly, sacred theology teaches us that, even though grace, faith, hope and charity spread their heavenly influence and divine movements to the other faculties of the inferior part of the soul, they nevertheless reside and have their true natural dwelling in the superior part. Hence it follows that this same part is the real heart of the Christian soul, because divine charity can have no other abode than the heart which possesses it, according to the words of St. Paul: “The charity of God is poured forth in our hearts” (Rom. 5:5).