Many advocates for revamping immigration laws have tried to coax Congress into action over the years, but a particularly powerful one will be arriving next month: Pope Francis.

Lawmakers and immigration activists expect the pontiff’s message will resonate beyond Capitol Hill and inspire members of Congress and their constituents. The pope’s U.S. schedule includes an address to Congress on Sept. 24 and a meeting two days later with immigrants and Hispanic families at Philadelphia’s Independence Mall.

“He’s been clear on our failure to respond appropriately to immigrants and refugees,” Rep. Jim McGovern, D-Mass., told CQ. “I don’t think anyone will have any doubt on where the church stands on immigration after the pope visits the United States.”

Pope Francis has been vocal about the treatment of immigrants since he became the head of the Roman Catholic Church in March 2013. Last year, he called the surge of Central American children crossing the border into the United States a “humanitarian emergency.” In a June encyclical letter on climate change, Francis noted the “tragic rise” of immigrants fleeing poverty.

The Holy Father would enter the United States by crossing the Mexican border if he had the time, according to Cardinal Oscar Rodríguez Maradiaga, the head of a papal advisory group of cardinals, during remarks in March before a Georgetown University audience.

McGovern, one of 169 Catholics in Congress, noted many Catholics might not be familiar with the church’s catechism that “more prosperous nations are obliged, to the extent they are able, to welcome the foreigner in search of the security and the means of livelihood, which he cannot find in his country of origin.”

He said he hopes the pope’s words will affect his colleagues who are opposed to a comprehensive immigration overhaul and encourage them to reflect on their actions.

“It may move some, it may not move others,” McGovern told CQ. “But I hope it makes those who have been obstructionist feel uncomfortable.”

Efforts to pass a comprehensive immigration bill stalled in the 113th Congress. Earlier this month, Senate Majority Leader  Mitch McConnell, R-Ky., said there would be no all-encompassing immigration legislation this year or next because of President  Barack Obama’s executive actions.

But advocates are hoping Francis will lend some momentum to a body where nearly a third of its members are Catholic. Several members in leadership are Catholic, including House Minority Leader Nancy Pelosi, D-Calif., House Majority Whip Steve Scalise, R-L.A., and Senate Minority Whip Richard J. Durbin, D-Ill.

Also on that list is House Speaker John A. Boehner, R-Ohio, a devout Catholic who has invited the last three popes to address Congress.

Boehner told reporters last month that he is not planning on picking any fights with the pontiff. He is looking forward to meeting the pope and hearing his speech, said spokeswoman Emily Schillinger.

“It will be the first time a pope has visited our Capitol building and also the first time a Pope has addressed a joint session of Congress,” she said in a statement. “While we cannot predict his remarks, we expect he’ll discuss issues that are important to Americans from all walks of life and on both sides of the aisle.”

Immigration advocates would like the pope’s words to translate into action by Congress, whether it’s a sweeping immigration bill or by working to end family detention centers. Jeanne Atkinson, executive director for the Catholic Legal Immigration Network, said the biggest impact of the pope’s speech could come from outside Washington, D.C.

“It will have some impact, and that impact will motivate people to reach out to their member of Congress,” she said. “What I would like to see come out of it is people becoming aware of this issue and aware that the church cares about it and from there trying to educate themselves further.”