On 15 May 1956 the Venerable Pope Pius XII issued his encyclical on devotion to the Sacred Heart of Jesus, Hauerietis Aquas, and here is a brief excerpt from it:
…the Heart of the Incarnate Word is deservedly and rightly considered the chief sign and symbol of that threefold love with which the divine Redeemer unceasingly loves His eternal Father and all mankind.It is a symbol of that divine love which He shares with the Father and the Holy Spirit but which He, the Word made flesh, alone manifests through a weak and perishable body, since "in Him dwells the fullness of the Godhead bodily." It is, besides, the symbol of that burning love which, infused into His soul, enriches the human will of Christ and enlightens and governs its acts by the most perfect knowledge derived both from the beatific vision and that which is directly infused.And finally—and this in a more natural and direct way—it is the symbol also of sensible love, since the body of Jesus Christ, formed by the Holy Spirit, in the womb of the Virgin Mary, possesses full powers of feelings and perception, in fact, more so than any other human body.
Traditionally, the month of June is dedicated to the Most Sacred Heart of Jesus.
O God, who hast suffered the Heart of thy Son to be wounded by our sins, and in that very Heart hast bestowed on us the abundant riches of thy love; grant that the devout homage of our hearts which we render unto him may of thy mercy be deemed a recompence, acceptable in thy sight; through the same Jesus Christ our Lord, who liveth and reigneth with thee in the unity of the Holy Ghost ever, one God, world without end. Amen.