The Slate.com Review says:
When it says that the movie is "told by two Jews", they must mean the Coen brothers.It’s a film about faith, and the pivotal role that it plays in one man’s search for meaning amidst the chaos of existence. It’s a tale of the Christ, told by two Jews who wouldn’t trust Jesus to save a cat out of a tree, let alone someone’s mortal soul.
Is the movie implying that the Virgin Mary secretly had sex out of marriage (raped like in the movie?) and then Jesus was adopted?Hail, Caesar! takes one of the diverse back catalogs in American cinema and forces its various components into a reluctant conversation that changes them all, like strangers who are forced into small talk at a cocktail party only to realize that they have the whole world in common. The Coens tackled the Old Testament with A Serious Man, and with Hail, Caesar! they’ve moved on to the New.
Introduced inside of a dark confession booth, Mannix is starting to doubt the value of his work and the worth of the pictures that he tirelessly endeavors to make possible. Mannix isn’t worried about hits or flops; he’s worried about the cosmic purpose of the film industry, and the existential value of his role in sustaining it. Suffering for the sins of a make-believe world, Mannix is effectively the Jesus Christ of the backlot, and he’s waiting to be crucified at any minute. His faith is being tested. Over the course of 36 hours, each one of which assumes the weight of mortality, Mannix will be forced to find meaning amidst chaos and to believe—truly believe—in something bigger than himself.
The Virgin Mary of this story, Moran is pregnant with the child of a married man, and it’s up to Mannix to defuse the scandal and protect his starlet’s brand of innocence. He knows exactly what to do—he lives for this.
The Coen Brothers’ Hail, Caesar! Is Silly, Epic, and One of Their Very Best
The Slate review references the part where Clooney forgets his line as a Roman soldier talking about Christianity "...if only we had faith":
But here’s the thing: Capitol Pictures is a disaster. We only see its films in fragments, but most of those fragments are terrible. Baird Whitlock’s biblical epic looks hammy enough to eat for Christmas dinner
...the value of filmmaking [is argued] to a universe of indelible characters who are struggling to understand it for themselves. It’s a truth they could see if only they had faith. And that, ultimately, is what Hail, Caesar! argues with greater clarity—if not always greater force—than any of the Coens’ previous films. There is no meaning but that which we convince ourselves. It doesn’t matter if you adhere to communism, religion, or movies: The only way you can believe in yourself is if you believe in something bigger.
The Coen Brothers’ Hail, Caesar! Is Silly, Epic, and One of Their Very Best