Archbishop Angelo Comastri, of the Italian Shrine of Loreto, delivered that message today on the first full day of the Spiritual Exercises that John Paul II is listening in on.
"Christianity is based on the certainty that God has entered in the history of men and, if God has entered in the history of men, it is possible to encounter God," Archbishop Comastri told the retreatants from the Roman Curia.
"It is possible to approach God, it is even possible to see God. And those who encounter God, those who see God, necessarily become witnesses of God," the archbishop added in the summary of his meditation, which was broadcast on Vatican Radio.
John Paul II and his closest aides in the Roman Curia heard the archbishop preach in the Redemptoris Mater Chapel of the Vatican Apostolic Palace. The retreat ends Saturday.
"An encounter is necessary to be able to witness," the preacher said. "The Apostle Paul encountered Jesus on the road to Damascus. After that encounter, Paul could not be held back.
"It is estimated that the apostle traveled some 8,000 kilometers on foot and between 9,000 and 10,000 kilometers by ship. Why? Because he could not hold back the fire he felt after his encounter with Jesus."
Referring to the conditions to encounter God and to experience his love, the archbishop said, "It is given to us once again by the Word of God, the Old and New Testament."
"On several occasions the Old Testament says that 'those called by God' and those who respond to God are only those who are humble," he said.
"Abraham is an elderly man called to become a father," Archbishop Comastri continued, offering a biblical example. "It might have seemed a joke, but, no, it was not a joke, it was a challenge to pride and Abraham overcame the challenge. He was humble and believed."
"In the Gospel, we realize that Mary is the humblest creature. In Mary, the experience of God reaches the highest," he said. "Her openness to God was so intense, so great, because Mary's heart was the humblest heart to have appeared on the face of the earth."
"This is the conclusion of this first day" of the Spiritual Exercises, the preacher explained. "Let us be humble," he said, adding that it is "an indispensable condition to encounter God and to be witnesses of God."
During the weeklong retreat, John Paul II will not hold any public audiences.