DULLES, Va. — In an auditorium on America Online's rolling campus, a glorious expanse of the heavens is projected on a big screen. Reggie Evans, a former Redskins running back turned emissary of Christ, has come to spread the Holy Word in the secular corridors of one of the biggest, richest Internet companies in the world. He has brought along some football cards and a stack of Bibles.

About 75 Christian workers listen as Evans advises them to carry out their work as if Jesus were sitting next to them. But when he suggests that they knock on a colleague's cubicle and propose, "Here's a Bible, maybe we can read this together," even the most devout among them know they will not be following his advice.

"My eyes rolled back when I heard that," said Jack Clark, a technical project manager and member of a recently formed employee group called Christians@AOL, which had invited Evans to speak. "We're not here to convert people."

Pushed primarily by evangelical Christians, faith is finding a growing presence in corporations that for years have been resistant to religious expression, including such giants as AOL Inc., Intel Corp., American Express Co., American Airlines Inc. and Ford Motor Co.

But it is an uneasy, risk-prone experiment. An evangelical movement emboldened by its strength in the 2004 presidential election, and pressing hard to advance its agenda in the battles over abortion and same-sex marriage, is finding that it must accept limits to secure a place in the corporate world.

Companies are allowing employees to sing the Lord's praises only according to strict rules — at lunch and on breaks, and only to those who want to listen — to minimize the threat to workplace harmony. Proselytizing, which can be seen as intrusive and a possible violation of harassment laws, is not permitted.

In return, some companies let workers share Bible verses on the company listserv, advertise religious events on the company intranet and invite inspirational speakers such as Evans to read Scripture in the corporate auditorium.

Even with those limits, however, the introduction of religion is changing the workplace atmosphere. Although it frees Christians such as Clark to bring their "whole selves" to work, it troubles many who are unaccustomed to seeing a Bible on a desk or hearing a supervisor respond to a casual "How's it going?" with an earnest "I'm blessed."

One AOL executive who recently passed through the company's glass lobby stopped short when the electronic bulletin board — which usually lists snow days or changes in the dental plan — advertised a seminar called "God at Work."