It’s worth remembering that he’s not the first pope to make this comparison.
“The émigré Holy Family of Nazareth, fleeing into Egypt, is the archetype of every refugee family. Jesus, Mary and Joseph, living in exile in Egypt to escape the fury of an evil king, are, for all times and all places, the models and protectors of every migrant, alien and refugee of whatever kind who, whether compelled by fear of persecution or by want, is forced to leave his native land, his beloved parents and relatives, his close friends, and to seek a foreign soil.” — Pope Pius XII, Exsul Familia Nazarethana
+“In this misfortune experienced by the Family of Nazareth, obliged to take refuge in Egypt, we can catch a glimpse of the painful condition in which all migrants live, especially, refugees, exiles, evacuees, internally displaced persons, those who are persecuted. We can take a quick look at the difficulties that every migrant family lives through, the hardships and humiliations, the deprivation and fragility of millions and millions of migrants, refugees and internally displaced people. The Family of Nazareth reflects the image of God safeguarded in the heart of every human family, even if disfigured and weakened by emigration.” — Pope Benedict XVI, Message for World Day of Migrants and Refugees, 2007
+“This Sunday is World Day of Migrants and Refugees, which every year invites us to reflect on the experience of numerous men and women and a great many families who leave their homeland in search of a better standard of living. Migration is sometimes voluntary and at other times, unfortunately, is forcefully imposed by war or persecution and often happens — as we know — in dramatic circumstances. The Office of the United Nations High Commissioner for Refugees (UNHCR) was set up 60 years ago for this reason. On the Feast of the Holy Family, straight after Christmas, we recalled that Jesus’ parents were also obliged to flee from their country and seek refuge in Egypt, to save the life of their Child: the Messiah, the Son of God was a refugee.”—Pope Benedict XVI, Angelus, January 16, 2011.
+“So many other footsteps are hidden in the footsteps of Joseph and Mary. We see the tracks of entire families forced to set out in our own day. We see the tracks of millions of persons who do not choose to go away but, driven from their land, leave behind their dear ones. In many cases this departure is filled with hope, hope for the future; yet for many others this departure can only have one name: survival. Surviving the Herods of today, who, to impose their power and increase their wealth, see no problem in shedding innocent blood. Mary and Joseph, for whom there was no room, are the first to embrace the One who comes to give all of us our document of citizenship. The One who in his poverty and humility proclaims and shows that true power and authentic freedom are shown in honoring and assisting the weak and the frail.”—Pope Francis, Christmas homily 2017