The Infancy Narratives in the gospels of Mathew and Luke are filled with rich symbolism. The Evangelists were Christians of the first century whose lives were dramatically changed after the death and resurrection of Jesus. It was their deep faith in Jesus and their concrete experience of the Christian community that informed the theology that permeates the Christmas story.
Matthew’s Gospel begins with a long list of Jesus’s ancestors down to Joseph. Whereas Mary is the key figure for Luke, Joseph is the protagonist of Matthew’s infancy narrative.
We’re told Joseph was a “righteous man,” for one very important reason: when he found out Mary was pregnant before they lived together, he planned to divorce her quietly
. It’s only when an angel tells him how it happened and who Jesus really is, that he changes his mind.
That’s the backdrop for Jesus’s birth in Matthew’s Gospel, and it tells us something very important about Joseph: According to the law, he should have separated from Mary. That was his right, and the only way to maintain his own image. But, without knowing how Mary was impregnated, he chose to go beyond the law, and to show mercy
. He put Mary’s dignity and reputation ahead of his own.
For Matthew, the Christmas story starts there. Joseph reminds us that a “righteous” person is not someone who simply follows to the law, but when faced with a very complex situation, they recognize that mercy is the "fullness of justice" and the "most radiant manifestation of God’s truth." (Amoris Laetitia 311
“One will never understand the infancy narratives without first being convinced that all Gospel material has been colored by the faith and experience of the church of the first century.”
Fr. Raymond Brown, SS, "An Adult Christ at Christmas"