Pope Francis said it is time to end indifference and what he calls "false neutrality" regarding the injustice, persecution, wars and misery in the world.
Whilst celebrating Mass in St Peter's Basilica he said that people wonder how it is possible that "the arrogance of the powerful continues to demean the weak, relegating them to the most squalid outskirts of our world".
He described how families are risking everything, including life, to flee from extreme war, hunger and persecution.
The pope urged people to overcome indifference and "leave behind the false neutrality which prevents sharing".
He stressed the co-operation could lead to peace in "an ever more just and fraternal world", he also added that he wondered how long human evil will keep producing violence and hatred.
Before celebrating Mass, the Pope also told a 6,000 strong group of young choristers that he cannot sing: "I like to hear singing.
"But if I would sing, it would seem like a donkey," he said.