VATICAN CITY, JAN. 19, 2005 ( Without prayer and "inner conversion" there can be no true ecumenism, says John Paul II.

The Pope made that point today at the general audience as he took note of the Week of Prayer for Christian Unity, which started Tuesday.

The Week of Prayer is observed Jan. 18-25 in most countries and aims to bring together the world's 2 billion Christians for prayer and reflection.

"They are extremely opportune days of reflection and prayer," the Holy Father said, "to remind Christians that the restoration of full unity among them, according to the will of Jesus, involves every baptized person, both pastors as well as the faithful."

Addressing several thousand people gathered in Paul VI Hall, the Pope noted that this Week of Prayer takes place months after the 40th anniversary of the Second Vatican Council's decree "Unitatis Redintegratio," a "key text which has placed the Catholic Church firmly and irrevocably in the line of the ecumenical movement."

The theme presented for meditation this year by the World Council of Churches and the Pontifical Council for Promoting Christian Unity is "Christ, the Only Foundation of the Church."

The Holy Father called the theme "a fundamental truth for all ecumenical commitment."

Quoting Vatican II, he explained: "Given that the reconciliation of Christians surpasses human powers and capacities, prayer gives expression to hope that does not disappoint, to trust in the Lord who makes all things new.

"But prayer must be accompanied by purification of the mind, the feelings and the memory. Thus it becomes an expression of that 'inner conversion,' without which there is no true ecumenism."

"In a word," John Paul II said, "unity is a gift of God, a gift to be tirelessly implored with humility and truth."

The Holy Father sounded optimistic, saying that the "desire for unity is spreading and deepening, touching new environments and contexts, arousing fervor for works, initiatives and reflections."

"Recently the Lord has also enabled his disciples to engage in important contacts of dialogue and collaboration. The pain of separation is felt with ever greater intensity, given the challenges of a world that awaits a clear and unanimous evangelical testimony on the part of all believers in Christ," he said.

As in past years, in Rome the Week of Prayer will end with the celebration of vespers on Jan. 25 in the Basilica of St. Paul Outside the Walls. The ceremony will be presided over by Cardinal Walter Kasper, president of the Pontifical Council for Promoting Christian Unity, and attended by representatives of other Christian Churches and confessions.

The Pope added: "I also ask you to pray so that the whole family of believers may attain as soon as possible the full communion desired by Christ."