The Sacred Heart is “the symbol of the love with which Jesus continually loves the eternal Father and all human beings without exception” (CCC, Glossary). The term also refers to the human heart of Jesus, Whose humanity is substantially united to the Word of God, the Second Person of the Blessed Trinity. In Jesus, there is only one Person, that is, one personal subject, but two natures. This is what we mean when we say that Jesus is both true God (divine nature) and true man (human nature). When Jesus says, “I am the way, the truth and the life,” He is speaking as the divine Son, the Word of God, and as a man like us. Jesus loves us in the fullness of His divinity and with His human heart.
This is what the Catechism of the Catholic Church has to say, about “the heart of the Incarnate Word”:
Jesus knew and loved us each and all during his life, his agony and his Passion, and gave himself up for each one of us: “The Son of God. . . loved me and gave himself for me.” He has loved us all with a human heart. For this reason, the Sacred Heart of Jesus, pierced by our sins and for our salvation, “is quite rightly considered the chief sign and symbol of that. . . love with which the divine Redeemer continually loves the eternal Father and all human beings” without exception (478).1
- To read more from the Catechism of the Catholic Church on the Incarnation – https://www.vatican.va/archive/ccc_css/archive/catechism/p122a3p1.htm