"A distinction must be made between multireligious and interreligious prayer," the cardinal says in "Fede, verità, tolleranza -- Il cristianesimo e le religioni del mondo" (Faith, Truth, Tolerance -- Christianity and the World Religions), released by Cantagalli Publishers.
The prayers for peace in Assisi, called by John Paul II, are multireligious, as all participants pray at the same time but in different places.
In these cases, the participants "know that their way of understanding the divinity and, therefore, their way of addressing it, is so different that a common prayer would be a fiction, it would not be true," writes Cardinal Ratzinger, the prefect of the Congregation for the Doctrine of the Faith.
On the contrary, in interreligious prayers, people of diverse religious traditions pray together, he explains.
"Is it possible to do so in a truthful and honest way?" the author asks. He responds by saying that he seriously doubts it.
If such interreligious prayers are organized, however, they require three conditions, Cardinal Ratzinger stresses.
First, he says, it must be made clear that one is praying to the one, personal God; second, it must be established that what is being prayed for is not in contradiction to the Our Father; and third, it must be stressed that for Christians Jesus Christ is the sole redeemer of all people.