This morning the first thought that came to my mind was Luke 12.51 in which Jesus said to his Apostles, "Do you think I have come to establish peace on the earth? No, I tell you, but rather division." It so happened that the reading at Mass from Matthew 10 was on that same saying: "Do not think that I have come to bring peace upon the earth. I have come to bring not peace but the sword." And later in Matthew 25, speaking about the final judgment, Jesus said to his disciples, "When the Son of Man comes in his glory, and all the angels with him, he will sit upon his glorious throne, and all the nations will be assembled before him. And he will separate them one from another, as a shepherd separates the sheep from the goats. He will place the sheep on his right and the goats on his left." The division finalized.
So this is the reality of life. Having inherited the original sin from our ancestors, we all became sinners. Then God loved us so much that he gave his only Son so that whoever believes in him might not perish but might have eternal life. The division comes about when we do not all believe in the Son. The ball is in our court.