The Vatican described the retreat as “a propitious occasion for reflection and prayer, as well as an occasion for encounter and reconciliation.”

Aboard the papal plane, Francis spoke with reporters about the need to build solidarity, not barriers.

Pope Francis suggested four actions were needed to assist migrants in their plight today: “accept; protect; promote; and integrate.”

Pope Francis said he hoped his visit would “strengthen the bonds of sincere friendship,” mutual respect and cooperation between Christians and Muslims “and enable our communities to prepare a better future for coming generations.”

“I come as a pilgrim of peace and fraternity, in a world that greatly needs it,” the pope said in a video message to the “dear people of Morocco” on the eve of his visit this weekend.

A combination of a rapidly growing population, extreme poverty, unemployment and armed conflict push people to cross Nigeria’s porous borders in search of a better life.