There are three issues top of mind for Boston residents, according to Mayor Wu, and they are “housing, housing, housing,” she told a large crowd gathered at Temple Israel in the city’s Longwood area last week, adding, “housing, and how expensive it is, how unaffordably out of reach it is.”

Housing was the focus of the gathering, put together by the Dorchester-based Greater Boston Interfaith Organization (GBIO). The event drew a mix of politicians, clergy, and private sector leaders: Lt. Gov. Kim Driscoll, who wore the title of acting governor because Maura Healey was traveling in Ireland; newly appointed Healey housing chief Ed Augustus, Worcester’s former city manager; Mattapan state Rep. Brandy Fluker Oakley; and Cape Cod state Sen. Julian Cyr, among others. Rev. Burns Stanfield, who heads a Presbyterian congregation in South Boston, serves as the GBIO’s chair.

“Housing is what determines the safety of our communities, the vibrancy of our communities, the solidarity of our communities,” Wu said. “And I’m so excited that you all are taking this on because there is power in this room.”

A key goal of the event was building support for a real estate transfer fee, which is backed by the Wu administration. Legislation on Beacon Hill calls for a fee ranging between 0.5 percent and 2 percent on transactions above $1 million, with the money going to an affordable housing trust fund. Municipalities would be able to opt into such a fee, and under the latest version, cities and towns can create exemptions if they choose.

Realtors oppose the fee, which is also called a tax.

The concept has drawn support from Thomas O’Brien, a developer with the HYM Investment Group and a former director of the Boston Redevelopment Authority. His company is behind the creation of 12,000 units of housing, 2,200 of them affordable.

“But it’s not enough,” he said in a statement issued after the GBIO’s gathering. “We must build more, and I agree with the GBIO that we must all work together to solve this problem. If a transfer fee can be created that does not adversely affect current homeowners, has an upper limit on commercial transactions, and in which the proceeds are dedicated to housing production and preservation, I would be for it.”

Another piece of legislation that GBIO supports is a bill allowing inmates released from incarceration to have priority access to state-funded housing and vouchers.

Fluker Oakley said the bill “will not only remove a major barrier to accessing resources that can connect our neighbors to housing opportunities, but it also has the potential to reduce recidivism and make our communities more vibrant places where we all can thrive.”