Spaces after abbreviated book names
If the style calls for the book name to be abbreviated and to have a period after the abbreviation, then there needs to be some protection against said period being interpreted as ending a sentence. Based on my testing, I think that if there is a chapter/verse citation, then the space between the book name and the chapter number comes out right, but if the citation is only to a book name, then it does not.
Using chicago
style compare \bibleverse{IITh} test
to \bibleverse{IITh}\ test
to \bibleverse{IITh}(1:) test
. In the first case the space between "Thess." and "test" is wider than in other two (which have the same amount of space between "Thess." and the next element).