Catechism of the Catholic Church
478 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." 116 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, 117 "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. 118
479 At the time appointed by God, the only Son of the Father, the eternal Word, that is, the Word and substantial Image of the Father, became incarnate; without losing his divine nature he has assumed human nature.
480 Jesus Christ is true God and true man, in the unity of his divine person; for this reason he is the one and only mediator between God and men.
481 Jesus Christ possesses two natures, one divine and the other human, not confused, but united in the one person of God's Son.
482 Christ, being true God and true man, has a human intellect and will, perfectly attuned and subject to his divine intellect and divine will, which he has in common with the Father and the Holy Spirit.
483 The Incarnation is therefore the mystery of the wonderful union of the divine and human natures in the one person of the Word.
English Translation of the Cathechism of the Catholic Church for the United States of America © 1997, United States Catholic Conference, Inc.