Religious broadcaster Pat Robertson and Family Research Council president Tony Perkins topped a full day of speakers at "The America for Jesus 2012" prayer rally.
Robertson, a former Republican candidate for president, called the election important, but didn't mention either major political party or candidate by name.
"I don't care what the ACLU says or any atheists say. This nation belongs to Jesus, and we're here today to reclaim his sovereignty," said Robertson, 82, who founded the Christian Coalition and Christian Broadcasting Network, and ran for president in 1988.
Organizers plan another prayer rally Oct. 20 in Washington, D.C., two weeks before President Barack Obama faces Republican Mitt Romney in the presidential election.
Perkins asked the crowd to pray for elected officials including Obama.
"We pray that his eyes will be open to the truth," Perkins said.
A number of event organizers, though, have been vocal critics of the Democratic president.
Steve Strang, the influential Pentecostal publisher of Charisma magazine, which was distributed at the rally, recently wrote in a blog post that America is under threat from a "radical homosexual agenda." He also said Obama "seems to be moving toward some form of European socialism.
And speaker Cindy Jacobs has blamed a mysterious Arkansas bird-kill last year on Obama's repeal of the policy known as "don't ask, don't tell," which allows gays and lesbians to serve openly in the military.
Speakers throughout the day condemned abortion, gay marriage and population control as practiced by Planned Parenthood. Christian rock music filled the historic mall as speakers challenged the crowd to overcome the seven deadly sins: pride, greed, lust, envy, gluttony, wrath and slothfulness.
Lisa Hodges, 41, made the trip with friends from her church in Tarboro, N.C. A single mother and grandmother, she is concerned about the election but hasn't made a final decision on her vote. She has doubts that Obama is a Christian, as he professes to be, but also wants to know more about Romney's Mormon religion.
She hopes the country will return to what she called its "godly foundations" through prayer in school and an emphasis on "purity."
The rally was held outside of Independence Hall, where the Declaration of Independence was signed. Pennsylvania is also where evangelist George Whitefield preached during the first Great Awakening, the 18th-century religious revival that spread through the American colonies.
Earlier this month, the ministry coalition behind the event distributed food and offered medical care throughout Philadelphia as part of their outreach.
Nyree Reed, 38, of Willingboro, N.J., wept Saturday as she listened to speeches about the sex trade in Asia and other worldly problems.
"I feel we really failed God because we haven't been following the rules and the system that he set out for us," said Reed, standing next to her husband Douglas. "I'm not even thinking about the election right now. People need to be saved. People need to be helped.