In a preceding chapter we have proved that the Devotion existed many centuries before the time of Blessed Margaret Mary. Occasional references may be found as early as the fifth century alluding expressly to the Sacred Heart. They become quite frequent in the works of Mediaeval Saints and spiritual writers, and after the middle of the fifteenth century they are countless in number. From that time on the pictured and sculptured representations of the Sacred Heart have multiplied rapidly. The Devotion assumed a fairly definite shape in the century immediately preceding that of Blessed Margaret Mary, and even merited the approbation of a number of local prelates. It is not an exaggeration to say that — irrespective of the supernatural manifestations with which Christ deigned to favor this humble Visitandine — the cult of the Sacred Heart would have eventually claimed its rightful place among the various devotions of the Church. Such a conclusion is warranted by the rapid development of the cult and the popularity it enjoyed, especially in the time of Father Eudes. Thus, the revelations did no more than hasten an event which, in the ordinary course of things — judging from the facts as they were gradually unfolding themselves to the perspective — was practically inevitable.
The principle on which the Devotion to the Sacred Heart rests is far from being a new discovery. St. Thomas in his attempt to elucidate it makes use of the following well-known comparison: We may consider two things in a person to whom honor is given, viz., the person himself and the cause of his being honored. Properly speaking, honor is given to a subsistent thing in its entirety; for we do not speak of honoring a man's hand or foot, these members not being honored of themselves, but the whole man being honored in them. In this way a man may be honored even in something external; for instance, in his vesture, his image or his messenger. Guided by this reasoning the theologians conclude that the primary material object of the Devotion to the Sacred Heart is Jesus Christ Himself in His Entirety. Hence, a cult like that of the Sacred Heart, properly speaking, is a latreutic co-adoration, for we adore the Heart with the rest of the parts of Christ's sacred Humanity, including His divine prerogatives. Thus the Heart is worshipped directly (secundum se and in se), not for its own sake, nor on account of its intrinsic excellence (propter se), but on account of its borrowed dignity.
