Citing the biblical account of Cain and Abel, the Pope said that the question God made to Cain regarding the whereabouts of his brother is repeated to every generation.
"Unfortunately, in every generation the tragic answer of Cain also does not cease to be repeated: "I do not know; am I my brother’s keeper?" the Pope said. "But when the fraternal bond between brothers is broken, it becomes something awful and also evil for humanity. And in families also, how many brothers have argued over little things or for an inheritance, and then they do not speak to one another anymore, they do not greet each other anymore. This is awful!"
Regarding the role of brothers and sisters, the 78 year old Pontiff stressed that the relationship they share within the family is a school of freedom and peace. Peaceful coexistence within society is first learned in the context of brotherhood within the family.
"Beginning from this first experience of brotherhood, nourished by affections and family education, the style of brotherhood is radiated as a promise over the whole society and its relations between peoples," he said.
"The blessing that God, in Jesus Christ, pours down on this bond of brotherhood,expands it in an unimaginable way, rendering it capable of going beyond every difference of nation, language, culture and even of religion."
The Pope noted the beauty of brotherhood that goes beyond family life, when one shows care for another person as a brother or sister. History, he said, "has shown us sufficiently, however, that, without fraternity, freedom and equality can also be filled with individualism and conformity."
Another aspect is that of an older sibling caring for a younger brother and sister, especially if they are sick or handicapped.
"There are very many brothers and sisters in the whole world who do this, and perhaps we do no appreciate their generosity enough," he said. "And when there are many brothers in a family – today I greeted a family there that has nine --, the greatest help to the father, to the mother is to take care of the little ones. And this work of help between brothers is beautiful!"
Prior to concluding his address, Pope Francis led the faithful present in silent prayer, asking them to remember their brothers and sisters. "With this prayer, we have brought all our brothers and sisters with our thought and with our heart here, to the Square, to receive the blessing. Thank you!" he said.