22 The other reason which refers in a particular manner to the Heart of the divine Redeemer, and likewise demands in a special way that the highest form of worship be paid to it, arises from the fact that His Heart, more than all the other members of His body, is the natural sign and symbol of His boundless love for the human race. "There is in the Sacred Heart," as Our predecessor of immortal memory, Leo XIII, pointed out, "the symbol and express image of the infinite love of Jesus Christ which moves us to love in return."(16)
Source: Haurietis Aquas (Vatican.va)