"The ecumenical encounter is preserved in its profound significance according to a spirit of unity, that is my desire."
Pope Francis also spoke at length about his relationship with Lutherans while still in Buenos Aires, which were overwhelmingly positive. When asked what Catholics can learn from Lutherans, he responded with two words: "reform and Scripture."
Referring to the first word, Francis noted how at the beginning of the Reformation Martin Luther's intention was to reform in a "in a difficult time for the Church."
"Luther wanted to remedy a complex situation," he said, explaining that the gesture "also because of the political situations... became a 'state' of separation, and not a process of reform of the whole Church, which is fundamental, because the Church is semper reformanda (always reforming)."
When it comes to Scripture, the Pope said Luther did an important thing by putting the Word of God into peoples' hands, adding that "reform and Scripture are two things that we can deepen by looking at the Lutheran tradition."
Although the fervor for unity that arose during John Paul II's visit to Sweden in 1989 has somewhat died down, Pope Francis said that in his opinion, the best way to promote unity now is, in addition to continuing theological discussions, a shared enthusiasm for "common prayer and the works of mercy."
"It is important to work together and not in a sectarian way," he said, stressing that "to proselytize in the ecclesial field is a sin."
"Proselytism is a sinful attitude," he continued. "It would be like transforming the Church into an organization. Speaking, praying, working together: this is the path that we must take."
He also spoke of the ecumenism of blood and the recent prayer encounter in Assisi, insisting that you can never use God to justify violence.
"You cannot make war in the name of religion, in the name of God. It is blasphemy, it is satanic," and referring to the truck attack that took place earlier this year in Nice, France, said the "madman" who committed the massacre did so believe he was justified by God.
"Poor man, he was deranged," Francis said, explaining that "charitably we can say that he was a deranged man who sought to use a justification in the name of God."
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He was also asked about critics who point to religous conflicts and say the world would be better off without religions.
In response, Francis sand that "idolatries that are at the base of a religion, not the religion itself!"
"There are idolatries connected to religion: the idolatry of money, of enmities, of space greater than time, the greed of the territoriality of space. There is an idolatry of the conquest of space, of dominion, that attacks religions like a malignant virus."
Idolatry, he said, is "a false religion" and "wrong religiosity."
On the other hand, true religions "are the development of the capacity that humanity has to transcend itself towards the absolute," he said, adding that the religious phenomenon is transcendent and it has to do with truth, beauty, goodness and unity."
When asked for a final word on his upcoming trip, Pope Francis said that what came to him spontaneously to say "is simply: go, walk together! Don't remain closed in rigid perspectives, because in these there is no possibility of reform."