"I don't care what the ACLU says or any atheist says, this nation belongs to Jesus," Robertson said.
The 82-year-old founder of the 700 Club who sought the Republican nomination for president in 1988, spoke to the "America for Jesus 2012" crowd estimated by a park ranger at 8,000 to 10,000, The Philadelphia Inquirer reported.
The rally was part of a two-day event organized by a coalition of ministries called One Nation under God.
The group is calling for 40 days of prayer leading up to the presidential election.
Robertson's speech was interrupted by anti-abortion protester Rives Grogan, who said he is a pastor of the New Beginnings Christian Church in Los Angeles and expressed his support for Mitt Romney for president over President Barack Obama, the newspaper said.
"Obama is sin. Support Mitt Romney," Grogan shouted.
At one point, Robertson commanded Grogan to "shut your mouth" because "this is not political." Robertson also admonished Grogan for disrespecting the prayer gathering.
Participants surrounded Grogan and began praying for him, but he kept shouting.