Christianese: "The Lord works in mysterious ways."
Translation: "I'm totally clueless."
Common examples include: old man/new man, unblemished lamb, fruit of the spirit, washed in the blood, and let's not forget the ever popular born again.
Non-Christian: What the hell did you just say? You speakin' Christianese?
Translation: "I am going to hurt you now... in Jesus's name, Amen."