For all of Donald Trump's talk about his Christian beliefs, his faith is still in question, theology professor Chad Pecknold said Friday.
"Mr. Trump says he's a Christian? Tell us how the biblical principles guide him," the Catholic University of America professor told CNBC's "Squawk Box." "I think that's a legitimate question no one has asked."
Pecknold made his remarks a day after Pope Francis said the GOP front-runner was "not Christian" because of his views on immigration.