CAA: Christian Anime Alliance

I need someone who knows Japanese to help me with something.

How would you say "foreigner in this world", in Japanese? Like how Jesus said we are supposed to be different from the rest of the world. I'm thinkin ______ gaijin. I tried lookin it up, but there were like 121 definitions, so I thought I'd just ask here instead.

you could go with "sekai no gaijin," but i'm not sure how acceptable that would be in Japanese grammar since i'm thinking it from the top of my head. literally, that would translate as "the foreigner of the world."