It is not enough for Catholics to not do bad things, they must counter evil by actively living out charity in the performance of good deeds, Pope Francis told young people and others in St. Peter's Square Sunday.

"If we do not oppose evil, we feed it tacitly. It is necessary to intervene where evil spreads; because evil spreads where there are no daring Christians who oppose with good, 'walking in love,' according to the warning of St. Paul," the pope said Aug. 12.

Speaking to around 90,000 people in St. Peter's Square and the adjoining street before the recitation of the Angelus, Francis warned that people are guilty of the sin of omission when they could do something good but choose not to.

"It is not enough not to hate, it is necessary to forgive," he said. "It is not enough not to have a grudge, we must pray for [our] enemies… it is not enough to not speak badly about others, we must stop when we hear someone talking badly."

The pope addressed, in particular, Italian young people, who had made a pilgrimage to Rome as a way to pray for the upcoming Synod of Bishops on youth, urging them to be "protagonists of the good!"

He noted that because of the presence of the Holy Spirit, who dwells in every baptized person, Christians must strive to live their lives "in a coherent manner," renouncing evil, temptation, and sin, saying "no" to a culture of death, and by adhering to the good and doing good.

St. Paul urges in his letter to the Ephesians, remove "all bitterness, fury, anger, shouting, and reviling… along with all malice" and replace it with kindness, compassion, and forgiveness, "as God has forgiven you in Christ," Francis said.

He explained that many times he has heard people say that they do not hurt anyone with their actions – "All right but are you good?" the pope asked. To not do harm, but meanwhile neglect to live out the virtues, leads to apathy and indifference, he said.

Such an attitude is contrary to the Gospel and contrary to the character of young people, "who by nature are dynamic, passionate and courageous."

"Remember this," he said, quoting St. Albert Hurtado: "It is good not to do evil, but it is bad not to do good."

Noting the walking pilgrimage many of those present had made to reach Rome, he said, "therefore, you are trained and I can tell you: walk in love!"

"Let's walk together towards the next Synod of Bishops… May the Virgin Mary support us with her maternal intercession, so that each of us, every day, with deeds, can say 'no' to evil and 'yes' to good," he concluded.