The Archbishop of Vienna has warned that as Europe’s migrant crisis reaches a fever pitch, the continent risks falling into old fears that could build new walls that are contrary to the Christian concept of charity.

“Faced with the challenge of many migrants and refugees, which is a great challenge, there is the risk that everyone withdraws into their own limits; that the borders, barriers, walls, the Iron Curtain, will return, will exist again, even if in a different way,” Cardinal Christoph Schönborn said Jan. 18.

An “enormous challenge” for Europe is to have the Christian virtues of prudence, mercy, and charity overcome the fears and “new nationalisms which seem outdated,” but which are, in fact, alive and well, he said, adding that “we are again in a new wave of neo-nationalism in Europe.”

The cardinal spoke at a news conference presenting the European Apostolic Congress on Mercy, which is set to take place in Rome March 31-April 4 as part of the Jubilee of Mercy.

In response to the migrant-refugee situation, which hit Europe especially hard in 2015, “there are things to do on many levels,” especially for the Church and for politicians who have faith, he said.

“We must not forget that Europe was in blood and tears for centuries of wars between Christians,” the cardinal observed, and lamented that the continent which once prided itself on openness and acceptance seems to be falling into old mentalities of fear and closed-mindedness.

He said that European leaders, including those from the Church, haven’t yet been able to generate a unified response to large numbers of immigrants.

In 2015 alone more than 1 million migrants and refugees crossed into Europe, sparking a continent wide crisis that has created division in the EU on how best to handle the influx.

“I hope that European bishops have the ability to find a common word, a common encouragement. Right now we still haven’t gotten there, to be honest,” he said.

Cardinal Schönborn lamented that the Council of European Churches has been able to give neither a “strong word” on this challenge, “nor an analysis on the causes.”

However, whatever decisions are made, mercy must be at the heart, he said, pointing to the corporal and spiritual works of mercy, which are being encouraged during the Holy Year as a good source of reflection.

“A good policy is a work of mercy,” the cardinal said, adding that the fight against corruption, which is so important to Pope Francis, “is a work of mercy.”

The work done by courageous politicians “who fight at the risk of their lives against corruption is a work of mercy that we need on all levels,” he added.

Cardinal Schönborn then voiced his hopes for the outcome of the upcoming Apostolic Congress on Mercy.

The goal is that for attendees, mercy would become “not only devotion, but charity, mercy in action,” he said.

Witnesses of mercy are especially important on this point, he said, and pointed to his involvement in a death row case in the United States as an example.

Texas death row inmate Richard Masterson, is scheduled to be executed Jan. 20. Masterson was convicted in 2001 for the murder of Darin Shane Honeycutt, and has been on death row for 12 years.

According to Cardinal Schönborn, Pope Francis is also aware of Masterson’s case and pending execution.

“It’s a scary thing, to be executed tomorrow,” the cardinal said, and praised “the apostolate of mercy” being carried out by various groups of Christians who have been following the case since the beginning, including the Community of Sant’Egidio, urging prayer.

Without pointing to specifics, the cardinal said that what these groups are doing for Masterson and his family “is a witness of the closeness of Jesus to this man” which shows “the sweet experience of the merciful heart of Jesus.”