The Doctrine of the Sacred Heart Devotion:

When we think of the concept of “devotion,” we think in terms of true love, generosity, loyalty and such.  That is how we would describe a husband and father who is “devoted” to his wife and family. It is also how we’d describe someone who is devoted to the Sacred Heart.  But “devotion to the Sacred Heart” can mean something else. It can refer to the “cult” approved by the Church which involves the worship of the Sacred Heart of Jesus as He Himself requested.  This is beyond the devotion we might have to a certain saint or another pious practice. Devotion to the Sacred Heart of Jesus is a doctrinal cult by which we worship the Person of Jesus Christ symbolized by His Heart.  It is not on the level of any other devotion, not even devotion to the Mother of God. It is the devotion of devotions; the devotion to the love of Jesus, the Incarnate Word of God.
Pope Pius XII in his Sacred Heart Encyclical writes that “this devotion is nothing else than devotion to the divine and human love of the Incarnate Word and to the love by which the heavenly Father and the Holy Spirit exercise their care over sinful men.”
Every devotional practice approved by the Church is based on a doctrine, a dogma.  For instance, the devotion of the Rosary is based on the dogma of the divine Maternity.  The same is true with the practices of piety, the reparations that form a part of the Devotion to the Sacred Heart such as First Friday Communions, the Holy Hour and others.  What is the doctrine or dogma supporting this devotion? Very simple but also very important:  “GOD IS LOVE” (1 Jn 4:16).  This is the dogma that underlies all dogmas.
Every practice of devotion toward the Heart of Jesus is nothing other than an expression of these truths:  “God is Love. Jesus is God. Therefore, Jesus is Love. He loves me. I want to love Him in return.”
When our Lord wanted to remind us of His love, He showed us His Heart.  “Behold this Heart,” He said to St. Margaret Mary at Paray-le-Monial, “which has loved men so much.”  
-The blog post is an excerpt from David Karem talk at the 2019 Sacred Heart Congress, Columbus, OH.