Reasons for Devotion to the Sacred Heart of Jesus

Haurietis Aquas, an encyclical by Pius XII, gives six reasons why the Church gives the highest form of worship to the Heart of Jesus.

1. We recognize that His Heart is hypostatically united to the Person of the Divine Word. This is an article of faith defined in the general Council of Ephesus and the Second Council of Constantinople. 
2. Jesus' Heart, more than all the other members of His body, is the natural sign and symbol of His boundless love for us. Leo XIII told us it is "the symbol and express image of the infinite love of Jesus Christ that moves us to love in return."
3. God's love for us is proclaimed and insisted upon in the Old and New Testaments by the kind of images which strongly arouse our emotion.
4. Jesus had a human body and heart but Jesus Christ is hypostatically united to the Word with divine charity and infinite love itself which Jesus shares with the Father and the Holy Spirit.
5. It is the perfect symbol of divine love.
6. Since, therefore, Sacred Scripture and the official teaching of the Catholic faith instruct us that all things find their complete harmony and order in the most holy soul of Jesus Christ, and that He has manifestly directed His threefold love for the securing of our redemption, it unquestionably follows that we can contemplate and honor the Heart of the divine Redeemer as a symbolic image of His love and a witness of our redemption and, at the same time, as a sort of mystical ladder by which we mount to the embrace of "God our Savior."     Paragraph 58