21. This bond of charity was the core of the Holy Family's life, first in the poverty of Bethlehem, then in their exile in Egypt, and later in the house of Nazareth. The Church deeply venerates this Family, and proposes it as the model of all families. Inserted directly in the mystery of the Incarnation, the Family of Nazareth has its own special mystery. And in this mystery, as in the Incarnation, one finds a true fatherhood: the human form of the family of the Son of God, a true human family, formed by the divine mystery. In this family, Joseph is the father: his fatherhood is not one that derives from begetting offspring; but neither is it an "apparent" or merely "substitute" fatherhood. Rather, it is one that fully shares in authentic human fatherhood and the mission of a father in the family. This is a consequence of the hypostatic union: humanity taken up into the unity of the Divine Person of the Word-Son, Jesus Christ. Together with human nature, all that is human, and especially the family-as the first dimension of man's existence in the world-is also taken up in Christ. Within this context, Joseph's human fatherhood was also "taken up" in the mystery of Christ's Incarnation.

On the basis of this principle, the words which Mary spoke to the twelve-year-old Jesus in the Temple take on their full significance: "Your father and I...have been looking for you." This is no conventional phrase: Mary's words to Jesus show the complete reality of the Incarnation present in the mystery of the Family of Nazareth. From the beginning, Joseph accepted with the "obedience of faith" his human fatherhood over Jesus. And thus, following the light of the Holy Spirit who gives himself to human beings through faith, he certainly came to discover ever more fully the indescribable gift that was his human fatherhood.