Charlie Neibergall/AP Photo

Making his way to a stage that has become almost a litmus test for past Republican presidential hopefuls, Sen. Ted Cruz made a "call to action" today at one of the nation's largest gatherings of young Christians.

"If you believe in religious liberty, if you believe in standing for your faith, then I would encourage and call you to act," Cruz, R-Tex., told the crowd.

Cruz addressed a packed house of more than 10,000 students at the Liberty University, the world's largest Christian school, with thousands more watching online.

The school, founded by the late Rev. Jerry Falwell, has been a common stomping ground for politicians seeking the Republican presidential bid. Past speakers have included Mitt Romney, Mike Huckabee and Newt Gingrich.

Sen. Rand Paul, R-KY., a potential opponent to Cruz in 2016, spoke at Liberty University back last October.

Before showing the crowd a montage of Cruz's recent speeches at CPAC and various tea party rallies, University Chancellor Jerry Falwell Jr. told the crowd he was proud to introduce "the great Reaganite hope" and one of the lead voices speaking out to repeal Obamacare.

Falwell recalled Cruz's involvement in religious legal battles as an advocate for Christian groups before Cruz took to the stage, where he told students "religious liberty has never been more under assault" than under the Obama administration.

"How through the looking glass have we gone?" Cruz said. "We have a government litigating against our citizens trying to force us to violate our religious beliefs."

Later in the day, Cruz will address an Introduction to American Politics class taught by Larry Sabato, a director of the University of Virginia Center for Politics.

As for Liberty University, its next political guest will visit Thursday when Republican Party Chairman Reince Priebus addresses the school's College Young Republicans group.