23 It is of course beyond doubt that the Sacred Books never make express mention of a special worship of veneration and love made to the physical Heart of the Incarnate Word as the symbol of His burning love. But if this must certainly be admitted, it cannot cause us surprise nor in any way lead us to doubt the divine love for us which is the principal object of this devotion; since that love is proclaimed and insisted upon in the Old and in the New Testament by the kind of images which strongly arouse our emotions. Since these images were presented in the Sacred Writings foretelling the coming of the Son of God made man, they can be considered as a token of the noblest symbol and witness of that divine love, that is, of the most Sacred and Adorable Heart of the divine Redeemer.
Source: Haurietis Aquas (Vatican.va)