The ministers gathered Tuesday at the entrance to Steen Outdoor Advertising to protest the advertisement for ArrangementFinders.com, a website aimed at facilitating extra-marital affairs, the Philadelphia Daily News reported Wednesday.
"Thou Shalt Not Commit Adultery," the ad reads, with the word "not" crossed out.
Debra Hamilton, head of sales and marketing at Steen, said the company was also upset by the advertisement, but officials can't review content for the hundreds of advertisements put up by the firm.
However, A.J. Perkins, a marketing representative for the website, said the company had to approve the ad before it went up.
"They actually own the sign; they approve what goes up," he said. "Otherwise, it would have been a lot more risque, trust me."
Perkins said the sign has led to a 600 percent increase in the number of Philadelphia-area members since it was erected.