On Sunday, when Denver Bronco wide receiver Demaryius Thomas caught a pass from Tim Tebow on the first play of overtime and ran it all the way for a game-winning touchdown, the stadium erupted. At once, people cried that it was a miracle, and Mr. Tebow went down to pray on one knee in his signature pose. Millions of viewers already knew the first words he would say whenever a reporter caught up to him for a postgame interview: "First of all, I want to thank my Lord and Savior, Jesus Christ!"

Tim Tebow...