A colorful and enthusiastic crowd made up of members of more than 100 religious movements welcomed the pope in Saint Peter's Square waving flags and chanting. Some 350,000 people packed the square and neighboring streets.
Pope Benedict thanked them for turning up so numerous for a prayer service on the eve of Pentecost. In his homily, the pope encouraged those present to make their faith clear to others.
He told them that he who has known something true, beautiful and good in life should run to share it around everywhere, in family and in work, in all the places of one's existence
The pope also said religious movements want and must be schools of freedom, of true freedom. "In this world, so full of false freedoms which destroy the environment and man, we want to learn together, with the strength of the Holy Spirit, true freedom, building schools of freedom, showing others with life that we are free and how beautiful it is to be truly free," he said.
Pope Benedict would also be holding mass on Sunday for members of religious movements.
Earlier on Saturday, the pope met in private audience at the Vatican with British Prime Minister Tony Blair. They discussed the role religion can play in politics and society and agreed on the importance of dialogue between faiths and cultures to tackle extremism and terrorism.
Pope Benedict and Mr Blair also discussed the needs for peaceful coexistence and development in Africa and discussed the religious situation in China, where the communist government does not allow the local Catholic Church to recognize the Pope.