World Youth Day proved a powerful experience for many, and the happy informality of the tens of thousands of young people became infectious in Sydney, irrespective of people's religious beliefs.
Rock stars would have envied Pope Benedict's ability to draw such vast crowds, but many church personnel were perturbed that a great opportunity was lost to demonstrate how intrinsic to the Gospel was concern for peacemaking, social justice and ecological sustainability.
The irony is that many younger people are passionately concerned about such matters, as Bono and the rock group U2 can attest with their mobilising of younger generations to the cause of the Millennium Development Goals.
Yet the main World Youth Day events failed to highlight a key biblical message: that God will judge us on how we have responded to the needs of the poor, sick, hungry and imprisoned. Jesus meant to shock his hearers. Piety is worthless in God's eyes if it ignores one's social responsibility, since God identifies intensely with people in distress.
World Youth Day offered an unprecedented chance to demonstrate how directly religious beliefs bear on urgent social issues such as social equity, world hunger, the energy crisis, global warming, the MDGs and peacemaking.
True, Benedict congratulated the new Australian government for its apologies for injustices against our indigenous peoples and commended Australia's role in international peacekeeping.
Later he added that 'non-violence, sustainable development, justice and peace, and care for our environment are of vital importance for humanity'.
But these crucial themes then vanished from centre stage, though many smaller events on the margins dealt with such issues, especially those organised by religious orders or social agencies like Caritas or Vinnies.
The neglect of the Church's own social justice teaching was doubly puzzling, since Benedict has spoken often on world poverty, climate change, the food crisis in many countries, along with threats from nuclear weapons, cluster bombs and the flourishing arms trade.
Benedict frequently discusses these issues with world leaders. To French President Sarkozy on 12 September he highlighted the role of religion in helping address social justice, protecting the environnement and human rights, and peace and reconciliation among peoples.
He wrote to British Prime Minister Gordon Brown in June, urging renewed determination to achieve the Millennium Development Goals. And at his meeting with President George W. Bush on 13 June, the Pope raised the topics of the food crisis, the Millennium Development Goals,