"Joseph became the guardian, the administrator, and the legal defender of the divine house whose chief he was. And during the whole course of his life he fulfilled those charges and those duties. He set himself to protect with a mighty love and a daily solicitude his spouse and the Divine Infant; regularly by his work he earned what was necessary for the one and the other for nourishment and clothing; he guarded from death the Child threatened by a monarch's jealousy…; in the miseries of the journey and in the bitternesses of exile he was ever the companion, the assistance, and the upholder of the Virgin and of Jesus.
Now the divine house which Joseph ruled with the authority of a father, contained within its limits the scarce-born Church. From the same fact that the most holy Virgin is the mother of Jesus Christ is she the mother of all Christians whom she bore on Mount Calvary amid the supreme throes of the Redemption; Jesus Christ is, in a manner, the first-born of Christians, who by the adoption and Redemption are his brothers. (Rm 8:29)
And for such reasons the Blessed Patriarch looks upon the multitude of Christians who make up the Church as confided specially to his trust - this limitless family spread over the earth, over which, because he is the spouse of Mary and the Father of Jesus Christ he holds, as it were, a paternal authority. It is, then, natural and worthy that as the Blessed Joseph ministered to all the needs of the family at Nazareth and girt it about with his protection, he should now cover with the cloak of his heavenly patronage and defend the Church of Jesus Christ."
-Leo XIII in his Encyclical Quanquam pluries.