Hathaway comments on the crucifixes in Will's flat, but we're shown ordinary crosses, not crucifixes, which are crosses with the crucified Christ. Since Hathaway studied to become a priest, he should know the difference.
Lewis: "Life born of fire." I bet that means something in Latin.
Hathaway: What makes you say that?
Lewis: This is Oxford. Everything always means something in Latin.
Hathaway: I was training to be a priest. Kind of closes your life down a bit. Then I was training to become a policeman.
Lewis: Closes down your life even more.
Hathaway: Thank heavens we found each other, sir.
Dr Hobson: Where's your better half?
Lewis: By that you mean Sergeant Hathaway?
Dr Hobson: I was gonna say your Mini Me, but I didn't think you'd get the pop culture reference.
Lewis: Don't be daft, woman. Even I've seen The Italian Job.
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Lady Hugh [ about Reverend King ]: "Whatsoever a man soweth, so shall he reap."
Lewis: An eye for an eye?
Lady Hugh: Well, I wouldn't go that far.
Lady Hugh justifies her dismissal of Reverend King with another Bible verse, Galatians 6:7.
Lady Hugh [ to Lewis ]: "The merciful man doeth good to his own soul", and that deserves a cup of tea at least.
Lady Hugh's response to Lewis' rescuing her from the angry mob is to quote part of Proverbs 11:17.
Dr Hobson: I was going to say mini-me but I don't think you'd get the pop-culture reference.
Which does of course refer to the Austin Powers movies, not "The Italian Job" as stated by Lewis.