Interestingly, there is a different idiom in Dutch, "to be more catholic than the Pope", which roughly translates to doing things excessively by the book
I mean you could probably ask this, but I don't know any idioms like this in Norwegian. Any rhetorical question where the answer is 'yes' would work I guess.
"Er himmelen blå?" "Er gresset grønt?"
Note that "catholic" has a slightly different meaning from "Catholic," and I suspect that the latter is what this question requires.
"Catholic" is Roman Catholic, while "catholic" refers to the Christian church universally. At least one creed used to use the latter "catholic" when I was a kid in a Methodist church, and my mother explained this to me.
Moreover, the word 'catholic' can be used (albeit somewhat unusually) to refer to something universal in general. "The catholic tastes of a society" or a "catholic dislike of the governor" would refer to a unanimous, universal sentiment in an area.
I came to the comments hoping someone might know the Norwegian word for the English definition of this "catholic."
Den roman-katolske paven er egentlig ikke den eneste figur som henvises med ordet "pope" i kristendom. Tradisjonelt hemvises lederen til den aleksandrienske kirka for en rekke kristne tro med "pope".