A stereotypical sign of moral hypocrisy is the waving of a Bible. The phrase "Bible thumper" refers not to a genuinely inspired Christian zealot, but to a Pharisee more intent on cramming Biblical dicta into others' heads than on repenting for his own sins (who will not remove the mote in his own eye, in that same Bible's words). While "Bible thumper" goes back only a century or so, these scripture-waving types are as old as the Pharisees Christ chastises in that very book. They've always abounded in life, and representations of them in literature precede Shakespeare. (Think of Chaucer's licentious fire-and-brimstone preacher, the Pardoner.) So when the puffed-up libertine Donald Trump appeared waving a Bible in front of a Washington D.C. church last month, using that book as a prop to help him condemn the folks in that city who were protesting police violence against black citizens, he was a familiar trope. (A Trump trope.) He was the real-life embodiment of a humorous literary and dramatic cliche. He didn't know that, of course, because he doesn't read books. But the fact was evident to others.
The joke was especially rich for Shakespeareans, who saw the resemblance of the ridiculous scene to the comic moment in Richard III when wicked Richard, Duke of Gloucester, stage-manages his own appearance in front of a crowd of London citizenry. He stands between two clergymen, holding a prayer book and claiming he is "earnest in the service of my God." He's suborned the mayor and his henchman Buckingham to urge him to leave his prayerful contemplation and ascend to the English throne -- a position to which he is not, in fact, entitled, but which he is determined to occupy. In Richard Loncraine's filmed adaptation of the play, Richard (Ian McKellen) and his sinister cronies wear Nazi-ish uniforms as they plot the scene.