District of Columbia Mayor Adrian M. Fenty signed into law a gay marriage bill on Friday, sparking a renewed push by opponents to ban the institution in the city.

Fenty, 39, signed the bill at a public ceremony at All Souls Church, a gay-friendly Unitarian Universalist congregation located in the diverse neighborhood of Columbia Heights.

Robert Hardies, All Souls' senior pastor, told the Washington Post that the church was “honored to be able to host this historic bill-signing.”

Hardies' work as co-chairman of D.C. Clergy United for Marriage Equality, a group of nearly 200 ministers who favor the legalization of gay marriage in the District, put his church in a favorable position to host the event.

“The signing of this bill marks a watershed moment for human rights in the District of Columbia,” Hardies told attendees. “No longer will gay and lesbian couples be denied the fundamental right to marriage in our nation's capital.”

“I applaud Mayor Fenty and the D.C. Council for standing on the side of love and ending discrimination against gay and lesbian Washingtonians,” he added.

But a second group of religious leaders are at the heart of an effort to block the bill from taking effect and want to ban the institution in the District.

Bishop Harry Jackson, a minister at the Hope Christian Church in Beltsville, Maryland formed Stand4MarriageDC.com in the spring after lawmakers approved a gay marriage-recognition bill and promised to legalize gay marriage.

The group's efforts to put a question prohibiting gay marriage on the ballot have been thwarted by the city's Ethics Board, which ruled such a measure would violate the city's Human Rights Act that prohibits discrimination based on sexual orientation. Jackson is appealing the ruling in a Superior Court.

After the bill received its second and final approval from city leaders on Tuesday, Jackson renewed his vow to take the question before voters. “Our day is going to come when the people get to vote on this. I think that's what's going to move people – outrage with a sense of urgency,” he said.

Opponents have also appealed to Congress to intervene. Under Home Rule, Congress has final say in all laws approved by the District. A process that must be completed within 30 legislative days of a bill becoming law.

Immediately after passage, the National Organization for Marriage (NOM), the nation's most vociferous opponent of gay marriage, broadcast an appeal to members to contact lawmakers on the issue.

“It's up to you and me to force Congress to deal with the issue!,” the organization said in an email to members. “Every member of Congress needs to hear from his or her own constituents that this is an urgent civil rights violation taking place in the District of Columbia that requires Congressional attention! Send your message to Congress today.”

Representative Jason Chaffetz, a Republican from Utah, has said he will introduce a resolution of disapproval. But passage in the Democrat-controlled Congress remains unlikely. A point even Chaffetz, a freshman representative, has conceded: “It's going to be exceptionally difficult because Democrats have us outnumbered by large amounts,” he told the Salt Lake Tribune Wednesday. “Nevertheless, we're going to try.”

Passage in the District might give efforts to approve a gay marriage bill in New Jersey a much needed boost. Enthusiasm for the bill appears to be on the wane after senators in nearby New York killed a similar bill last month and voters in Maine “vetoed” a gay marriage law approved by lawmakers in the spring.

If Congress fails to intervene, the measure is expected to take effect in February.