The most common and most likely answer to this crossword clue is the 8 letter word LECTERNS
I've seen this crossword clue in The Guardian
L
E
C
T
E
R
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S
More clues leading to the result LECTERNS
Buddy explains!

The straight part
We know that "Upholders of the Christian word" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case upholders of the christian word = lecterns.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does LECTERNS mean?
LECTERNS noun- A stand with a slanted top used to support a bible from which passages are read during a church service.
- A similar stand to support a lecturer's notes.